Merge develop into feat/git-sync — unify converter on the branch (#293/#326 step 6a)

Per maintainer directive (#119 comment): land the canonical converter on the git-sync branch so sync is tested on the real format, NOT a dead legacy copy. #119 itself stays FROZEN (не вливается) — this only merges develop in. Resolutions (all git-sync converter conflicts → develop; engine kept as-is): - Dropped the branch's legacy `packages/git-sync/src/lib/*` converter — the converter now lives solely in `@docmost/prosemirror-markdown` (#293); the engine (pull/push/stabilize/index) only switches its imports to the package (no logic change, verified by diff). - Removed the branch's orphaned converter tests + fixtures under `packages/git-sync/test/` (their coverage moved to the package's own test suite on develop); git-sync/test now holds engine tests only. - .gitignore / Dockerfile / test.yml / AGENTS.md: unioned — build/ ignored for every package; Dockerfile COPYs both prosemirror-markdown/build (mcp+git-sync runtime) and git-sync/build (git-sync's runtime consumer lands on this branch); CI builds prosemirror-markdown before git-sync/mcp. - pnpm-lock.yaml regenerated for the merged workspace. Branch adaptations to canon (server-side tests only — converter untouched, per the guardrail that converter fixes go to the package on develop, fixtures-first): - git-sync-converter-gate.spec.ts: heading textAlign and image width/height now round-trip via the canon trailing-comment forms (#9 ``, #4 ``) instead of the old HTML-tag forms — expectations flipped to the real canon output. RESIDUAL: canon #4 does not yet carry image `align` (documented as a known divergence; fix belongs in the package on develop). - schema-attribute-contract.spec.ts: the schema mirror moved from `@docmost/git-sync/lib/docmost-schema` to `@docmost/prosemirror-markdown`; import + jest source-mapper updated. Verified: prosemirror-markdown/git-sync/mcp build clean; git-sync corpus green; server `tsc --noEmit` 0; gate + schema-attribute-contract specs 32/32.
2026-07-04 20:09:26 +03:00
parent 7d9cf99f6c 4369bbc53d
commit e90624a51c
150 changed files with 10315 additions and 4868 deletions
@@ -1,5 +1,5 @@
 import { describe, it, expect, beforeEach, vi } from "vitest";
-import { render, screen, fireEvent, act } from "@testing-library/react";
+import { render, screen, fireEvent, act, cleanup } from "@testing-library/react";
 import { MantineProvider } from "@mantine/core";

 // Shared, hoisted mock state so the @ai-sdk/react and "ai" module mocks (hoisted
@@ -140,3 +140,91 @@ describe("ChatThread — send now (#198)", () => {
    expect(prep({ messages: [], body: {} }).body.interrupted).toBe(false);
  });
 });
+
+// The turn-end decision lives in the `onFinish` handler: given the terminal
+// outcome of a turn (`isAbort` / `isDisconnect` / `isError`, or none = clean),
+// it decides whether to CONTINUE (flush the next queued message) or END (leave
+// the queue intact for the user), and which stop notice — if any — to show.
+// `sendNow` is exercised above; these tests pin down the plain outcomes.
+describe("ChatThread — turn-end decision (onFinish)", () => {
+  beforeEach(() => {
+    h.state.status = "streaming";
+    h.state.onFinish = null;
+    h.state.sendMessage.mockClear();
+    h.state.stop.mockClear();
+    h.state.transport = null;
+  });
+
+  // Drive a fresh onFinish with the given terminal flags after queueing a
+  // message, and report both what the parent was told and whether the queue was
+  // flushed (a resend to the sendMessage spy).
+  function finishWith(flags: {
+    isAbort?: boolean;
+    isDisconnect?: boolean;
+    isError?: boolean;
+  }) {
+    // Tear down any prior render so the loop-driven "every outcome" case does
+    // not leave duplicate queue buttons in the DOM.
+    cleanup();
+    h.state.sendMessage.mockClear();
+    const { onTurnFinished } = renderThread();
+    // Populate the queue while the turn is streaming.
+    fireEvent.click(screen.getByTestId("queue-btn"));
+    act(() => {
+      h.state.onFinish?.({
+        message: { id: "a", role: "assistant", parts: [] },
+        isAbort: false,
+        isDisconnect: false,
+        isError: false,
+        ...flags,
+      });
+    });
+    return { onTurnFinished };
+  }
+
+  it("CONTINUES — flushes the next queued message on a clean finish", () => {
+    finishWith({});
+    // Clean finish (no terminal flag): the queued message is auto-sent.
+    expect(h.state.sendMessage).toHaveBeenCalledWith({ text: "queued text" });
+    // A clean finish shows no stop notice.
+    expect(screen.queryByText("Response stopped.")).toBeNull();
+  });
+
+  it("ENDS — keeps the queue intact on a user abort and shows the stopped notice", () => {
+    finishWith({ isAbort: true });
+    // A plain Stop (not the sendNow interrupt path) must NOT auto-resend: the
+    // queue is preserved for the user to decide.
+    expect(h.state.sendMessage).not.toHaveBeenCalled();
+    expect(screen.getByText("Response stopped.")).toBeTruthy();
+  });
+
+  it("ENDS — keeps the queue intact on a disconnect and shows the connection-lost notice", () => {
+    finishWith({ isDisconnect: true });
+    expect(h.state.sendMessage).not.toHaveBeenCalled();
+    expect(
+      screen.getByText("Connection lost — the answer was interrupted."),
+    ).toBeTruthy();
+  });
+
+  it("ENDS — keeps the queue intact on a stream error (no auto-retry, no stopped notice)", () => {
+    finishWith({ isError: true });
+    // Blindly retrying after a failure would be wrong; the queue is left alone.
+    expect(h.state.sendMessage).not.toHaveBeenCalled();
+    // isError clears the neutral notice (the error banner covers this case).
+    expect(screen.queryByText("Response stopped.")).toBeNull();
+  });
+
+  it("notifies the parent on EVERY terminal outcome", () => {
+    // The chat-list refresh / new-chat id adoption must run on success and on
+    // every failure path alike.
+    for (const flags of [
+      {},
+      { isAbort: true },
+      { isDisconnect: true },
+      { isError: true },
+    ]) {
+      const { onTurnFinished } = finishWith(flags);
+      expect(onTurnFinished).toHaveBeenCalled();
+    }
+  });
+});
@@ -8,6 +8,7 @@ import { IComment } from "@/features/comment/types/comment.types";
 // The comment mutation hooks reach out to react-query/network — stub them so the
 // component renders in isolation. We only assert the AI-badge rendering branch.
 const applyMutateAsync = vi.fn();
+const dismissMutateAsync = vi.fn();
 vi.mock("@/features/comment/queries/comment-query", () => ({
  useDeleteCommentMutation: () => ({ mutateAsync: vi.fn() }),
  useResolveCommentMutation: () => ({ mutateAsync: vi.fn() }),
@@ -16,6 +17,10 @@ vi.mock("@/features/comment/queries/comment-query", () => ({
    mutateAsync: applyMutateAsync,
    isPending: false,
  }),
+  useDismissSuggestionMutation: () => ({
+    mutateAsync: dismissMutateAsync,
+    isPending: false,
+  }),
 }));

 // CommentEditor pulls in the full TipTap editor stack; replace it with a stub.
@@ -24,7 +29,10 @@ vi.mock("@/features/comment/components/comment-editor", () => ({
 }));

 import CommentListItem from "./comment-list-item";
-import { canShowApply } from "@/features/comment/utils/suggestion";
+import {
+  canShowApply,
+  canShowDismiss,
+} from "@/features/comment/utils/suggestion";

 const baseComment = (over?: Partial<IComment>): IComment =>
  ({
@@ -38,14 +46,20 @@ const baseComment = (over?: Partial<IComment>): IComment =>
    ...over,
  }) as IComment;

-function renderItem(comment: IComment, canEdit = true) {
+function renderItem(
+  comment: IComment,
+  canEdit = true,
+  canComment = true,
+  userSpaceRole?: string,
+) {
  return render(
    <MantineProvider>
      <CommentListItem
        comment={comment}
        pageId="page-1"
-        canComment={true}
+        canComment={canComment}
        canEdit={canEdit}
+        userSpaceRole={userSpaceRole}
      />
    </MantineProvider>,
  );
@@ -108,10 +122,12 @@ describe("CommentListItem — suggested edit (#315)", () => {
    });

  it("renders the было→стало diff and an Apply button when canEdit and not applied/resolved", () => {
-    renderItem(suggestion(), true);
-    // Old text appears both as the selection quote and as the struck diff row.
+    const { container } = renderItem(suggestion(), true);
+    // Old text appears as the selection quote (a single unsplit Text node).
    expect(screen.getAllByText("old wording here").length).toBeGreaterThan(0);
-    expect(screen.getByText("new wording here")).toBeDefined();
+    // The new line is now rendered as per-fragment spans (intraline diff, #331),
+    // so it is no longer a single text node — assert the concatenated content.
+    expect(container.textContent).toContain("new wording here");
    // Apply button is present.
    expect(screen.getByRole("button", { name: "Apply" })).toBeDefined();
    // No Applied badge yet.
@@ -119,9 +135,9 @@ describe("CommentListItem — suggested edit (#315)", () => {
  });

  it("hides the Apply button when canEdit is false", () => {
-    renderItem(suggestion(), false);
-    // Diff still renders...
-    expect(screen.getByText("new wording here")).toBeDefined();
+    const { container } = renderItem(suggestion(), false);
+    // Diff still renders (as per-fragment spans, #331)...
+    expect(container.textContent).toContain("new wording here");
    // ...but no Apply button.
    expect(screen.queryByRole("button", { name: "Apply" })).toBeNull();
  });
@@ -157,6 +173,65 @@ describe("CommentListItem — suggested edit (#315)", () => {
  });
 });

+describe("CommentListItem — dismiss suggestion (#329)", () => {
+  const suggestion = (over?: Partial<IComment>): IComment =>
+    baseComment({
+      selection: "old wording here",
+      suggestedText: "new wording here",
+      ...over,
+    });
+
+  // A space admin (userSpaceRole="admin") satisfies the owner-or-admin gate
+  // regardless of who authored the comment; the tests below use it as the lever
+  // since the currentUser atom is unseeded (null) in this harness.
+  it("renders a Dismiss button alongside Apply when canEdit and canComment (owner/admin)", () => {
+    renderItem(suggestion(), true, true, "admin");
+    expect(screen.getByRole("button", { name: "Apply" })).toBeDefined();
+    expect(screen.getByRole("button", { name: "Dismiss" })).toBeDefined();
+  });
+
+  it("shows Dismiss but NOT Apply for an admin commenter who cannot edit", () => {
+    renderItem(suggestion(), false, true, "admin");
+    expect(screen.queryByRole("button", { name: "Apply" })).toBeNull();
+    expect(screen.getByRole("button", { name: "Dismiss" })).toBeDefined();
+  });
+
+  it("hides Dismiss when the viewer cannot comment", () => {
+    renderItem(suggestion(), false, false, "admin");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+    expect(screen.queryByRole("button", { name: "Apply" })).toBeNull();
+  });
+
+  it("hides Dismiss for a non-owner non-admin even with canComment (#338 F5: mirrors server 403)", () => {
+    // canComment=true but NOT a space admin and NOT the comment owner (the
+    // currentUser atom is null while the comment is authored by user-1), so the
+    // server would 403 a dismiss — the button must not be shown at all.
+    renderItem(suggestion(), false, true, "member");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+  });
+
+  it("hides Dismiss once the thread is resolved", () => {
+    renderItem(suggestion({ resolvedAt: new Date() }), true, true, "admin");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+  });
+
+  it("hides Dismiss (shows the Applied badge) once applied", () => {
+    renderItem(suggestion({ suggestionAppliedAt: new Date() }), true, true, "admin");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+    expect(screen.getByText("Applied")).toBeDefined();
+  });
+
+  it("calls the dismiss mutation when the Dismiss button is clicked", () => {
+    dismissMutateAsync.mockClear();
+    renderItem(suggestion(), true, true, "admin");
+    fireEvent.click(screen.getByRole("button", { name: "Dismiss" }));
+    expect(dismissMutateAsync).toHaveBeenCalledWith({
+      commentId: "c-1",
+      pageId: "page-1",
+    });
+  });
+});
+
 describe("canShowApply predicate", () => {
  const c = (over?: Partial<IComment>): IComment =>
    ({ suggestedText: "x", ...over }) as IComment;
@@ -182,3 +257,32 @@ describe("canShowApply predicate", () => {
    expect(canShowApply(c({ parentCommentId: "p" }), true)).toBe(false);
  });
 });
+
+describe("canShowDismiss predicate", () => {
+  const c = (over?: Partial<IComment>): IComment =>
+    ({ suggestedText: "x", ...over }) as IComment;
+
+  it("true when suggestion present, can comment, owner/admin, not applied/resolved, top-level", () => {
+    expect(canShowDismiss(c(), true, true)).toBe(true);
+  });
+  it("false without comment permission", () => {
+    expect(canShowDismiss(c(), false, true)).toBe(false);
+  });
+  it("false when not owner and not admin (#338 F5)", () => {
+    expect(canShowDismiss(c(), true, false)).toBe(false);
+  });
+  it("false when no suggestion", () => {
+    expect(canShowDismiss(c({ suggestedText: null }), true, true)).toBe(false);
+  });
+  it("false when already applied", () => {
+    expect(canShowDismiss(c({ suggestionAppliedAt: new Date() }), true, true)).toBe(
+      false,
+    );
+  });
+  it("false when resolved", () => {
+    expect(canShowDismiss(c({ resolvedAt: new Date() }), true, true)).toBe(false);
+  });
+  it("false for a reply comment", () => {
+    expect(canShowDismiss(c({ parentCommentId: "p" }), true, true)).toBe(false);
+  });
+});
@@ -1,6 +1,6 @@
 import { Group, Text, Box, Badge, Button } from "@mantine/core";
 import { AgentAvatarStack } from "@/components/ui/agent-avatar-stack.tsx";
-import React, { useEffect, useRef, useState } from "react";
+import React, { useEffect, useMemo, useRef, useState } from "react";
 import classes from "./comment.module.css";
 import { useAtom, useAtomValue } from "jotai";
 import { useTimeAgo } from "@/hooks/use-time-ago";
@@ -13,11 +13,16 @@ import { useHover } from "@mantine/hooks";
 import {
  useApplySuggestionMutation,
  useDeleteCommentMutation,
+  useDismissSuggestionMutation,
  useResolveCommentMutation,
  useUpdateCommentMutation,
 } from "@/features/comment/queries/comment-query";
 import { IComment } from "@/features/comment/types/comment.types";
-import { canShowApply } from "@/features/comment/utils/suggestion";
+import {
+  canShowApply,
+  canShowDismiss,
+  computeSuggestionDiff,
+} from "@/features/comment/utils/suggestion";
 import { CustomAvatar } from "@/components/ui/custom-avatar.tsx";
 import { currentUserAtom } from "@/features/user/atoms/current-user-atom.ts";
 import { useTranslation } from "react-i18next";
@@ -51,9 +56,28 @@ function CommentListItem({
  const deleteCommentMutation = useDeleteCommentMutation(comment.pageId);
  const resolveCommentMutation = useResolveCommentMutation();
  const applySuggestionMutation = useApplySuggestionMutation();
+  const dismissSuggestionMutation = useDismissSuggestionMutation();
  const [currentUser] = useAtom(currentUserAtom);
  const createdAtAgo = useTimeAgo(comment.createdAt);

+  // Intraline "before -> after" diff (#331) for a suggested edit: only the
+  // fragments that actually changed get emphasised inside the red/green block,
+  // instead of striking through / greening the whole line. Memoised on the
+  // (selection, suggestedText) pair so it recomputes only when they change.
+  const suggestionDiff = useMemo(
+    () =>
+      comment.suggestedText != null
+        ? computeSuggestionDiff(comment.selection ?? "", comment.suggestedText)
+        : null,
+    [comment.selection, comment.suggestedText],
+  );
+
+  // Owner-or-space-admin gate (#338): mirrors the server authz for both the
+  // comment menu (edit/delete) and the suggestion Dismiss button, so we never
+  // render an action the server will 403.
+  const isOwnerOrAdmin =
+    currentUser?.user?.id === comment.creatorId || userSpaceRole === "admin";
+
  useEffect(() => {
    setContent(comment.content);
  }, [comment]);
@@ -115,6 +139,19 @@ function CommentListItem({
    }
  }

+  async function handleDismissSuggestion() {
+    try {
+      await dismissSuggestionMutation.mutateAsync({
+        commentId: comment.id,
+        pageId: comment.pageId,
+      });
+    } catch (error) {
+      // Idempotent races are reconciled to success in the mutation's onError;
+      // anything else surfaces there as a notification.
+      console.error("Failed to dismiss suggestion:", error);
+    }
+  }
+
  function handleCommentClick(comment: IComment) {
    const el = document.querySelector(
      `.comment-mark[data-comment-id="${comment.id}"]`,
@@ -190,7 +227,7 @@ function CommentListItem({
                />
              )}

-              {(currentUser?.user?.id === comment.creatorId || userSpaceRole === 'admin') && (
+              {isOwnerOrAdmin && (
                <CommentMenu
                  onEditComment={handleEditToggle}
                  onDeleteComment={handleDeleteComment}
@@ -236,12 +273,28 @@ function CommentListItem({
        {!comment.parentCommentId && comment.suggestedText && (
          <Box className={classes.suggestionBlock}>
            {comment.selection && (
+              // Old line: read as removed as a whole (line-through/red); only the
+              // changed fragments carry the extra intraline emphasis.
              <Text size="xs" className={classes.suggestionOld}>
-                {comment.selection}
+                {suggestionDiff?.old.map((segment, index) => (
+                  <span
+                    key={index}
+                    className={segment.changed ? classes.suggestionChanged : undefined}
+                  >
+                    {segment.text}
+                  </span>
+                ))}
              </Text>
            )}
            <Text size="xs" className={classes.suggestionNew}>
-              {comment.suggestedText}
+              {suggestionDiff?.new.map((segment, index) => (
+                <span
+                  key={index}
+                  className={segment.changed ? classes.suggestionChanged : undefined}
+                >
+                  {segment.text}
+                </span>
+              ))}
            </Text>

            {comment.suggestionAppliedAt ? (
@@ -255,18 +308,42 @@ function CommentListItem({
                {t("Applied")}
              </Badge>
            ) : (
-              canShowApply(comment, canEdit) && (
-                <Button
-                  size="compact-xs"
-                  variant="light"
-                  color="green"
-                  mt={6}
-                  onClick={handleApplySuggestion}
-                  loading={applySuggestionMutation.isPending}
-                  disabled={applySuggestionMutation.isPending}
-                >
-                  {t("Apply")}
-                </Button>
+              (canShowApply(comment, canEdit) ||
+                canShowDismiss(comment, canComment, isOwnerOrAdmin)) && (
+                <Group gap="xs" mt={6}>
+                  {canShowApply(comment, canEdit) && (
+                    <Button
+                      size="compact-xs"
+                      variant="light"
+                      color="green"
+                      onClick={handleApplySuggestion}
+                      loading={applySuggestionMutation.isPending}
+                      disabled={
+                        applySuggestionMutation.isPending ||
+                        dismissSuggestionMutation.isPending
+                      }
+                    >
+                      {t("Apply")}
+                    </Button>
+                  )}
+                  {/* Dismiss ("Не применять", #329): removes the suggestion
+                      without changing the page text. Gated on canComment. */}
+                  {canShowDismiss(comment, canComment, isOwnerOrAdmin) && (
+                    <Button
+                      size="compact-xs"
+                      variant="subtle"
+                      color="gray"
+                      onClick={handleDismissSuggestion}
+                      loading={dismissSuggestionMutation.isPending}
+                      disabled={
+                        applySuggestionMutation.isPending ||
+                        dismissSuggestionMutation.isPending
+                      }
+                    >
+                      {t("Dismiss")}
+                    </Button>
+                  )}
+                </Group>
              )
            )}
          </Box>
@@ -53,6 +53,21 @@
    margin-top: 4px;
 }

+/* Intraline diff (#331): the fragment that actually changed within the
+   red "before" / green "after" block. It inherits the surrounding red/green
+   framing and adds a stronger tint plus bold weight so the eye lands on the
+   changed letters/words (git/GitHub-style) rather than the whole line. The
+   container's line-through (old) / green (new) still marks the full line. */
+.suggestionChanged {
+    /* Stronger tint of the surrounding red/green so the changed fragment pops
+       within the block. `currentColor` follows the parent's red (old) or green
+       (new) text colour. No `text-decoration` here on purpose: the old block's
+       inherited line-through must survive on the changed letters too. */
+    background: color-mix(in srgb, currentColor 22%, transparent);
+    border-radius: 2px;
+    font-weight: 700;
+}
+
 .commentEditor {

    &[data-editable][data-surface="muted"] .ProseMirror:not(.focused) {
@@ -0,0 +1,279 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import React from "react";
+import { renderHook, waitFor } from "@testing-library/react";
+import {
+  QueryClient,
+  QueryClientProvider,
+  InfiniteData,
+} from "@tanstack/react-query";
+
+/**
+ * Coverage for the ephemeral-suggestion (#329) cache reconciliation in
+ * useApplySuggestionMutation / useDismissSuggestionMutation: the mutations act on
+ * the server `outcome` — 'deleted' drops the comment from the local list,
+ * 'resolved' relocates it (by stamping resolvedAt, which the tabs split on).
+ */
+
+vi.mock("@mantine/notifications", () => ({
+  notifications: { show: vi.fn() },
+}));
+
+vi.mock("@/features/comment/services/comment-service", () => ({
+  applySuggestion: vi.fn(),
+  dismissSuggestion: vi.fn(),
+  createComment: vi.fn(),
+  updateComment: vi.fn(),
+  deleteComment: vi.fn(),
+  resolveComment: vi.fn(),
+  getPageComments: vi.fn(),
+}));
+
+import { notifications } from "@mantine/notifications";
+import {
+  applySuggestion,
+  dismissSuggestion,
+} from "@/features/comment/services/comment-service";
+import {
+  useApplySuggestionMutation,
+  useDismissSuggestionMutation,
+  RQ_KEY,
+} from "@/features/comment/queries/comment-query";
+import { IComment } from "@/features/comment/types/comment.types";
+
+const PAGE_ID = "page-1";
+
+function seededClient(comment: IComment) {
+  const queryClient = new QueryClient({
+    defaultOptions: { mutations: { retry: false } },
+  });
+  const seed: InfiniteData<any> = {
+    pageParams: [undefined],
+    pages: [{ items: [comment], meta: { hasNextPage: false, nextCursor: null } }],
+  };
+  queryClient.setQueryData(RQ_KEY(PAGE_ID), seed);
+  const wrapper = ({ children }: { children: React.ReactNode }) => (
+    <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+  );
+  return { queryClient, wrapper };
+}
+
+function items(queryClient: QueryClient): IComment[] {
+  const cache = queryClient.getQueryData(RQ_KEY(PAGE_ID)) as
+    | InfiniteData<any>
+    | undefined;
+  return cache?.pages.flatMap((p) => p.items) ?? [];
+}
+
+const comment = (over?: Partial<IComment>): IComment =>
+  ({
+    id: "c-1",
+    pageId: PAGE_ID,
+    content: "{}",
+    creatorId: "u-1",
+    workspaceId: "ws-1",
+    createdAt: new Date(),
+    suggestedText: "new",
+    ...over,
+  }) as IComment;
+
+describe("useApplySuggestionMutation — outcome handling (#329)", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("outcome=deleted → removes the comment from the list", async () => {
+    vi.mocked(applySuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "deleted",
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+  });
+
+  it("outcome=resolved → keeps the comment and stamps resolvedAt/applied fields", async () => {
+    const resolvedAt = new Date();
+    vi.mocked(applySuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "resolved",
+      resolvedAt,
+      resolvedById: "u-1",
+      resolvedBy: { id: "u-1", name: "A" },
+      suggestionAppliedAt: resolvedAt,
+      suggestionAppliedById: "u-1",
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    const list = items(queryClient);
+    expect(list).toHaveLength(1);
+    expect(list[0].resolvedAt).toBe(resolvedAt);
+    expect(list[0].suggestionAppliedAt).toBe(resolvedAt);
+  });
+});
+
+describe("useDismissSuggestionMutation — outcome handling (#329)", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("outcome=deleted → removes the comment from the list", async () => {
+    vi.mocked(dismissSuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "deleted",
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+  });
+
+  it("outcome=resolved → keeps the comment and stamps resolvedAt", async () => {
+    const resolvedAt = new Date();
+    vi.mocked(dismissSuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "resolved",
+      resolvedAt,
+      resolvedById: "u-1",
+      resolvedBy: { id: "u-1", name: "A" },
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    const list = items(queryClient);
+    expect(list).toHaveLength(1);
+    expect(list[0].resolvedAt).toBe(resolvedAt);
+  });
+
+  it("idempotent race (404) → treated as success, comment removed from the list", async () => {
+    vi.mocked(dismissSuggestion).mockRejectedValue({
+      response: { status: 404 },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    // mutateAsync rejects even though onError reconciles the cache; swallow it.
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+    // #338 F3: the idempotent race must still fire the SUCCESS toast, not just
+    // silently drop the comment.
+    expect(notifications.show).toHaveBeenCalledWith({
+      message: "Suggestion dismissed",
+    });
+  });
+
+  it("dismiss 400 (thread still alive) → NOT a success, comment kept, no green toast (#338 F2)", async () => {
+    // 400 means the thread is alive (already resolved / a reply raced in).
+    // Narrowed onError: only 404 is a success-noop; 400 must surface a real error
+    // and keep the comment in the cache.
+    vi.mocked(dismissSuggestion).mockRejectedValue({
+      response: { status: 400 },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    // Comment NOT dropped from the cache.
+    expect(items(queryClient)).toHaveLength(1);
+    // A real (red) error, never the success message.
+    expect(notifications.show).toHaveBeenCalledWith(
+      expect.objectContaining({ color: "red" }),
+    );
+    expect(notifications.show).not.toHaveBeenCalledWith({
+      message: "Suggestion dismissed",
+    });
+  });
+
+  it("APPLY idempotent race (404) → treated as success, comment removed from the list", async () => {
+    // After #329 an applied reply-less suggestion is hard-deleted, so a racing
+    // second apply hits 404 — must reconcile to success like dismiss, not a red
+    // error (restores the #315 apply idempotency).
+    vi.mocked(applySuggestion).mockRejectedValue({
+      response: { status: 404 },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+    // #338 F3: the idempotent race must still fire the SUCCESS toast.
+    expect(notifications.show).toHaveBeenCalledWith({
+      message: "Suggestion applied",
+    });
+  });
+
+  it("APPLY 400 (thread resolved, not applied) → NOT a success, comment kept, red error (#338 F2)", async () => {
+    // apply's only 400 is "Cannot apply … on a resolved comment thread" — the
+    // thread was resolved (often with discussion) but NOT applied. It must be a
+    // real error surfacing the server message, and must NOT drop the live thread.
+    vi.mocked(applySuggestion).mockRejectedValue({
+      response: {
+        status: 400,
+        data: {
+          message: "Cannot apply a suggested edit on a resolved comment thread",
+        },
+      },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    // The live thread is NOT dropped from the cache.
+    expect(items(queryClient)).toHaveLength(1);
+    // Surfaces the server's specific message as a red error, never a success.
+    expect(notifications.show).toHaveBeenCalledWith(
+      expect.objectContaining({
+        message: "Cannot apply a suggested edit on a resolved comment thread",
+        color: "red",
+      }),
+    );
+    expect(notifications.show).not.toHaveBeenCalledWith({
+      message: "Suggestion applied",
+    });
+  });
+});
@@ -8,6 +8,7 @@ import {
  applySuggestion,
  createComment,
  deleteComment,
+  dismissSuggestion,
  getPageComments,
  resolveComment,
  updateComment,
@@ -16,6 +17,7 @@ import {
  ICommentParams,
  IComment,
  IResolveComment,
+  ISuggestionOutcome,
 } from "@/features/comment/types/comment.types";
 import { notifications } from "@mantine/notifications";
 import { IPagination } from "@/lib/types.ts";
@@ -177,40 +179,121 @@ function updateCommentInCache(
  };
 }

+function removeCommentFromCache(
+  cache: InfiniteData<IPagination<IComment>>,
+  commentId: string,
+): InfiniteData<IPagination<IComment>> {
+  return {
+    ...cache,
+    pages: cache.pages.map((page) => ({
+      ...page,
+      items: page.items.filter((comment) => comment.id !== commentId),
+    })),
+  };
+}
+
+// Reconcile the local comment cache with an ephemeral-suggestion outcome (#329)
+// returned by apply/dismiss: 'deleted' → drop the comment (it disappeared);
+// 'resolved' → the thread had replies and was resolved, so carry the resolved
+// state through (which relocates it to the resolved tab).
+function applySuggestionOutcomeToCache(
+  queryClient: ReturnType<typeof useQueryClient>,
+  pageId: string,
+  commentId: string,
+  data: ISuggestionOutcome,
+) {
+  const cache = queryClient.getQueryData(RQ_KEY(pageId)) as
+    | InfiniteData<IPagination<IComment>>
+    | undefined;
+  if (!cache) return;
+
+  if (data.outcome === "deleted") {
+    queryClient.setQueryData(RQ_KEY(pageId), removeCommentFromCache(cache, commentId));
+    return;
+  }
+
+  // 'resolved' (or an older server that omits outcome): reflect the resolved
+  // state and the applied stamps (apply sets them; dismiss leaves them null).
+  queryClient.setQueryData(
+    RQ_KEY(pageId),
+    updateCommentInCache(cache, commentId, (comment) => ({
+      ...comment,
+      suggestionAppliedAt: data.suggestionAppliedAt,
+      suggestionAppliedById: data.suggestionAppliedById,
+      resolvedAt: data.resolvedAt,
+      resolvedById: data.resolvedById,
+      resolvedBy: data.resolvedBy,
+    })),
+  );
+}
+
 export function useApplySuggestionMutation() {
  const queryClient = useQueryClient();
  const { t } = useTranslation();

-  return useMutation<IComment, any, { commentId: string; pageId: string }>({
+  return useMutation<
+    ISuggestionOutcome,
+    any,
+    { commentId: string; pageId: string }
+  >({
    // No optimistic update: apply can fail with 409 (the commented text drifted),
    // so we only mutate the cache once the server confirms.
    mutationFn: ({ commentId }) => applySuggestion(commentId),
    onSuccess: (data, variables) => {
-      const cache = queryClient.getQueryData(
-        RQ_KEY(variables.pageId),
-      ) as InfiniteData<IPagination<IComment>> | undefined;
-
-      if (cache) {
-        queryClient.setQueryData(
-          RQ_KEY(variables.pageId),
-          updateCommentInCache(cache, variables.commentId, (comment) => ({
-            ...comment,
-            suggestionAppliedAt: data.suggestionAppliedAt,
-            suggestionAppliedById: data.suggestionAppliedById,
-            // The server auto-resolves the thread on apply — carry that through.
-            resolvedAt: data.resolvedAt,
-            resolvedById: data.resolvedById,
-            resolvedBy: data.resolvedBy,
-          })),
-        );
-      }
+      // Ephemeral (#329): the server hard-deletes the applied suggestion when the
+      // thread has no replies ('deleted') or resolves it when it does ('resolved').
+      applySuggestionOutcomeToCache(
+        queryClient,
+        variables.pageId,
+        variables.commentId,
+        data,
+      );

      notifications.show({ message: t("Suggestion applied") });
    },
-    onError: (err: any) => {
+    onError: (err: any, variables) => {
+      const status = err?.response?.status;
+      // Idempotent race (double-click, or apply↔dismiss): after #329 an applied
+      // reply-less suggestion is hard-deleted, so a second/racing apply hits 404
+      // (already gone). ONLY 404 is a real success-noop — drop it from the cache
+      // and report success, the user's intent is already satisfied (restores the
+      // #315 apply idempotency the ephemeral delete would otherwise break).
+      //
+      // 400 is NOT success (#338 F2): apply's only 400 is "Cannot apply … on a
+      // resolved comment thread" — the thread was resolved (often WITH a live
+      // discussion) but the edit was NOT applied. Treating it as "Suggestion
+      // applied" is a false success that also drops a live thread from the cache.
+      // The #315 idempotent repeat does NOT produce 400 (childless → 404;
+      // with-replies → 200), so we never lose idempotency by excluding it here.
+      if (status === 404) {
+        const cache = queryClient.getQueryData(RQ_KEY(variables.pageId)) as
+          | InfiniteData<IPagination<IComment>>
+          | undefined;
+        if (cache) {
+          queryClient.setQueryData(
+            RQ_KEY(variables.pageId),
+            removeCommentFromCache(cache, variables.commentId),
+          );
+        }
+        notifications.show({ message: t("Suggestion applied") });
+        return;
+      }
+      // 400 => the thread was resolved and the edit could not be applied. Show a
+      // real error and KEEP the comment in the cache (it is still alive). Prefer
+      // the server's specific message when it carries one.
+      if (status === 400) {
+        const serverMsg = err?.response?.data?.message;
+        notifications.show({
+          message:
+            typeof serverMsg === "string" && serverMsg.length > 0
+              ? serverMsg
+              : t("Failed to apply suggestion"),
+          color: "red",
+        });
+        return;
+      }
      // 409 => the commented text changed since the suggestion was made. Surface
      // a specific message (with the current text) rather than a generic error.
-      const status = err?.response?.status;
      const currentText = err?.response?.data?.currentText;
      if (status === 409 && typeof currentText === "string") {
        const shortText =
@@ -234,6 +317,58 @@ export function useApplySuggestionMutation() {
  });
 }

+export function useDismissSuggestionMutation() {
+  const queryClient = useQueryClient();
+  const { t } = useTranslation();
+
+  return useMutation<
+    ISuggestionOutcome,
+    any,
+    { commentId: string; pageId: string }
+  >({
+    mutationFn: ({ commentId }) => dismissSuggestion(commentId),
+    onSuccess: (data, variables) => {
+      // Ephemeral (#329): dismiss hard-deletes the suggestion when the thread has
+      // no replies ('deleted') or resolves it when it does ('resolved').
+      applySuggestionOutcomeToCache(
+        queryClient,
+        variables.pageId,
+        variables.commentId,
+        data,
+      );
+
+      notifications.show({ message: t("Suggestion dismissed") });
+    },
+    onError: (err: any, variables) => {
+      // Idempotent race (double-click, or apply↔dismiss): the comment is already
+      // gone (404). ONLY 404 is a real success-noop — drop it from the cache and
+      // report success, the user's intent (make it disappear) is satisfied.
+      //
+      // 400 is NOT success (#338 F2): it means the thread is still ALIVE (already
+      // resolved, or a reply raced in), so treating it as "dismissed" would drop
+      // a live thread from the cache. Show a real error and keep the comment.
+      const status = err?.response?.status;
+      if (status === 404) {
+        const cache = queryClient.getQueryData(RQ_KEY(variables.pageId)) as
+          | InfiniteData<IPagination<IComment>>
+          | undefined;
+        if (cache) {
+          queryClient.setQueryData(
+            RQ_KEY(variables.pageId),
+            removeCommentFromCache(cache, variables.commentId),
+          );
+        }
+        notifications.show({ message: t("Suggestion dismissed") });
+        return;
+      }
+      notifications.show({
+        message: t("Failed to dismiss suggestion"),
+        color: "red",
+      });
+    },
+  });
+}
+
 export function useResolveCommentMutation() {
  const queryClient = useQueryClient();
  const { t } = useTranslation();
@@ -3,6 +3,7 @@ import {
  ICommentParams,
  IComment,
  IResolveComment,
+  ISuggestionOutcome,
 } from "@/features/comment/types/comment.types";
 import { IPagination } from "@/lib/types.ts";

@@ -18,13 +19,24 @@ export async function resolveComment(data: IResolveComment): Promise<IComment> {
  return req.data;
 }

-export async function applySuggestion(commentId: string): Promise<IComment> {
+export async function applySuggestion(
+  commentId: string,
+): Promise<ISuggestionOutcome> {
  // Mirrors resolveComment: let axios reject on non-2xx so the mutation can read
  // the 409 body (`{ message, currentText }`) off err.response.data.
  const req = await api.post("/comments/apply-suggestion", { commentId });
  return req.data.data ?? req.data;
 }

+export async function dismissSuggestion(
+  commentId: string,
+): Promise<ISuggestionOutcome> {
+  // Dismiss ("Не применять") a suggested edit (#329): the server hard-deletes
+  // the comment (or resolves it when it has replies) and returns the outcome.
+  const req = await api.post("/comments/dismiss-suggestion", { commentId });
+  return req.data.data ?? req.data;
+}
+
 export async function updateComment(
  data: Partial<IComment>,
 ): Promise<IComment> {
@@ -60,6 +60,15 @@ export interface IResolveComment {
  resolved: boolean;
 }

+// Result of applying or dismissing an ephemeral suggested edit (#329). The
+// server hard-deletes the comment (`deleted`) unless the thread has replies, in
+// which case it is resolved (`resolved`). The returned comment fields carry the
+// resolved-branch state; `outcome` tells the client which optimistic action to
+// take (drop the comment vs. move it to the resolved tab).
+export type ISuggestionOutcome = IComment & {
+  outcome?: "deleted" | "resolved";
+};
+
 export interface ICommentParams extends QueryParams {
  pageId: string;
 }
@@ -0,0 +1,102 @@
+import { describe, it, expect } from "vitest";
+import { computeSuggestionDiff, Segment } from "@/features/comment/utils/suggestion";
+
+// Reconstruct the plain string from a segment stream — the diff must be
+// lossless (concatenating every fragment yields the original input).
+const join = (segments: Segment[]): string =>
+  segments.map((s) => s.text).join("");
+
+// The subset of segments (in order) that the UI would emphasise.
+const changed = (segments: Segment[]): string[] =>
+  segments.filter((s) => s.changed).map((s) => s.text);
+
+// Find the segment that contains a substring, to assert its `changed` flag.
+const segmentWith = (segments: Segment[], needle: string): Segment | undefined =>
+  segments.find((s) => s.text.includes(needle));
+
+describe("computeSuggestionDiff", () => {
+  it("highlights only the single changed letter in a one-letter edit", () => {
+    const { old, new: neu } = computeSuggestionDiff("заведем", "заведём");
+
+    // Lossless.
+    expect(join(old)).toBe("заведем");
+    expect(join(neu)).toBe("заведём");
+
+    // Old side: exactly the `е` is changed, the rest is common.
+    expect(changed(old)).toEqual(["е"]);
+    expect(old).toEqual([
+      { text: "завед", changed: false },
+      { text: "е", changed: true },
+      { text: "м", changed: false },
+    ]);
+
+    // New side: exactly the `ё` is changed.
+    expect(changed(neu)).toEqual(["ё"]);
+    expect(neu).toEqual([
+      { text: "завед", changed: false },
+      { text: "ё", changed: true },
+      { text: "м", changed: false },
+    ]);
+  });
+
+  it("marks the differing words changed but keeps the shared word common", () => {
+    const { old, new: neu } = computeSuggestionDiff(
+      "привет мир",
+      "здравствуй мир",
+    );
+
+    // Lossless.
+    expect(join(old)).toBe("привет мир");
+    expect(join(neu)).toBe("здравствуй мир");
+
+    // The shared trailing word stays common on both sides (no per-letter noise
+    // leaking across the differing words into `мир`).
+    expect(segmentWith(old, "мир")?.changed).toBe(false);
+    expect(segmentWith(neu, "мир")?.changed).toBe(false);
+
+    // The differing words are emphasised somewhere on each side.
+    expect(changed(old).length).toBeGreaterThan(0);
+    expect(changed(neu).length).toBeGreaterThan(0);
+    expect(changed(old).join("")).toContain("п"); // from `привет`
+    expect(changed(neu).join("")).toContain("зд"); // from `здравствуй`
+
+    // No changed fragment on either side touches the word `мир`.
+    expect(changed(old).some((t) => t.includes("мир"))).toBe(false);
+    expect(changed(neu).some((t) => t.includes("мир"))).toBe(false);
+  });
+
+  it("marks a whole inserted word changed and leaves the old line common", () => {
+    const { old, new: neu } = computeSuggestionDiff("a c", "a b c");
+
+    expect(join(old)).toBe("a c");
+    expect(join(neu)).toBe("a b c");
+
+    // Old line has no changed fragment (nothing was removed).
+    expect(changed(old)).toEqual([]);
+    // The inserted word is the only changed fragment on the new side.
+    expect(neu).toContainEqual({ text: "b ", changed: true });
+    expect(changed(neu)).toEqual(["b "]);
+  });
+
+  it("marks a whole deleted word changed and leaves the new line common", () => {
+    const { old, new: neu } = computeSuggestionDiff("a b c", "a c");
+
+    expect(join(old)).toBe("a b c");
+    expect(join(neu)).toBe("a c");
+
+    // The deleted word is the only changed fragment on the old side.
+    expect(old).toContainEqual({ text: "b ", changed: true });
+    expect(changed(old)).toEqual(["b "]);
+    // New line has no changed fragment (nothing was added).
+    expect(changed(neu)).toEqual([]);
+  });
+
+  it("marks everything common for identical strings", () => {
+    const { old, new: neu } = computeSuggestionDiff("hello", "hello");
+
+    expect(old).toEqual([{ text: "hello", changed: false }]);
+    expect(neu).toEqual([{ text: "hello", changed: false }]);
+    expect(changed(old)).toEqual([]);
+    expect(changed(neu)).toEqual([]);
+  });
+});
@@ -1,3 +1,4 @@
+import { diffWordsWithSpace, diffChars } from "diff";
 import { IComment } from "@/features/comment/types/comment.types";

 // Whether the suggested-edit (#315) "Apply" button should be shown for a
@@ -12,3 +13,127 @@ export function canShowApply(comment: IComment, canEdit?: boolean): boolean {
      !comment.parentCommentId,
  );
 }
+
+// One contiguous run of text within a suggestion's "before" or "after" line.
+// `changed` marks the fragment that actually differs from the other side, so
+// the UI can emphasise only the intraline delta (git/GitHub-style) instead of
+// the whole line.
+export interface Segment {
+  text: string;
+  changed: boolean;
+}
+
+// A pure "before -> after" intraline diff (#331): the old line split into
+// common vs. removed-and-changed fragments, and the new line split into common
+// vs. added-and-changed fragments. Concatenating each side's `text` reproduces
+// the original strings.
+export interface SuggestionDiff {
+  old: Segment[];
+  new: Segment[];
+}
+
+// Push a segment, coalescing runs of the same `changed` flag on the same side
+// so the render emits as few spans as possible and tests stay predictable.
+function pushSegment(segments: Segment[], text: string, changed: boolean): void {
+  if (text === "") return;
+  const last = segments[segments.length - 1];
+  if (last && last.changed === changed) {
+    last.text += text;
+  } else {
+    segments.push({ text, changed });
+  }
+}
+
+// Compute an intraline diff between the old `selection` and the new
+// `suggestedText` of a suggestion. PURE — no React, no DOM, no I/O.
+//
+// Hybrid word + char algorithm (per #331):
+//   1. `diffWordsWithSpace` yields word-granular parts [{value, added, removed}].
+//   2. An ADJACENT removed+added pair (a word replacement) is refined with
+//      `diffChars`: shared characters stay common, differing characters are
+//      marked `changed` on their respective side. This is what keeps a
+//      one-letter edit (заведем -> заведём) from highlighting the whole word.
+//   3. A lone `added` (insertion) or lone `removed` (deletion) marks the whole
+//      fragment `changed`.
+//   4. An unchanged part is `common` on both sides.
+//
+// Rejected alternatives: pure `diffChars` is noisy on word swaps; pure
+// `diffWordsWithSpace` highlights the whole word rather than the changed letter.
+export function computeSuggestionDiff(
+  oldStr: string,
+  newStr: string,
+): SuggestionDiff {
+  const oldSegments: Segment[] = [];
+  const newSegments: Segment[] = [];
+
+  const parts = diffWordsWithSpace(oldStr, newStr);
+
+  for (let i = 0; i < parts.length; i++) {
+    const part = parts[i];
+    const next = parts[i + 1];
+
+    // A word replacement: a removed part immediately followed by an added part
+    // (or the reverse). Refine it character-by-character so only the differing
+    // letters are highlighted while shared letters stay common.
+    const isReplacementPair =
+      next &&
+      ((part.removed && next.added) || (part.added && next.removed));
+
+    if (isReplacementPair) {
+      const removedPart = part.removed ? part : next;
+      const addedPart = part.added ? part : next;
+
+      const charParts = diffChars(removedPart.value, addedPart.value);
+      for (const cp of charParts) {
+        if (cp.added) {
+          pushSegment(newSegments, cp.value, true);
+        } else if (cp.removed) {
+          pushSegment(oldSegments, cp.value, true);
+        } else {
+          // Shared character: common on both sides.
+          pushSegment(oldSegments, cp.value, false);
+          pushSegment(newSegments, cp.value, false);
+        }
+      }
+
+      i++; // consume the paired part as well
+      continue;
+    }
+
+    if (part.added) {
+      // Lone insertion: only present in the new line, wholly changed.
+      pushSegment(newSegments, part.value, true);
+    } else if (part.removed) {
+      // Lone deletion: only present in the old line, wholly changed.
+      pushSegment(oldSegments, part.value, true);
+    } else {
+      // Unchanged: common on both sides.
+      pushSegment(oldSegments, part.value, false);
+      pushSegment(newSegments, part.value, false);
+    }
+  }
+
+  return { old: oldSegments, new: newSegments };
+}
+
+// Whether the suggested-edit (#329) "Не применять" (Dismiss) button should be
+// shown. Dismiss does NOT change the page text (so it needs only canComment, not
+// canEdit), BUT a childless dismiss IRREVERSIBLY hard-deletes the comment, so the
+// server gates it on comment-owner-OR-space-admin (#338 F5). The button must
+// mirror that authz or a non-owner non-admin sees a live Dismiss that always
+// 403s → red error. Hence isOwnerOrAdmin is required IN ADDITION to canComment.
+// Same not-applied/not-resolved/top-level conditions as Apply.
+export function canShowDismiss(
+  comment: IComment,
+  canComment?: boolean,
+  isOwnerOrAdmin?: boolean,
+): boolean {
+  return Boolean(
+    canComment &&
+      isOwnerOrAdmin &&
+      comment.suggestedText &&
+      !comment.suggestionAppliedAt &&
+      !comment.resolvedAt &&
+      !comment.parentCommentId,
+  );
+}
@@ -1,5 +1,5 @@
 import { useCallback } from "react";
-import { useAtom, useStore } from "jotai";
+import { useAtom, useSetAtom, useStore } from "jotai";
 import { notifications } from "@mantine/notifications";
 import { useTranslation } from "react-i18next";
 import { useNavigate, useParams } from "react-router-dom";
@@ -20,6 +20,7 @@ import {
 } from "@/features/page/queries/page-query.ts";
 import { buildPageUrl } from "@/features/page/page.utils.ts";
 import { getSpaceUrl } from "@/lib/config.ts";
+import { mobileSidebarAtom } from "@/components/layouts/global/hooks/atoms/sidebar-atom.ts";

 export type UseTreeMutation = {
  handleMove: (sourceId: string, op: DropOp) => Promise<void>;
@@ -43,6 +44,7 @@ export function useTreeMutation(spaceId: string): UseTreeMutation {
  const removePageMutation = useRemovePageMutation();
  const movePageMutation = useMovePageMutation();
  const navigate = useNavigate();
+  const setMobileSidebar = useSetAtom(mobileSidebarAtom);
  const { spaceSlug, pageSlug } = useParams();

  const handleMove = useCallback(
@@ -201,8 +203,23 @@ export function useTreeMutation(spaceId: string): UseTreeMutation {
        createdPage.title,
      );
      navigate(pageUrl);
+      // On mobile the create action is triggered from inside the off-canvas
+      // sidebar drawer (space sidebar "+", tree-row "add subpage"). Navigating
+      // alone leaves that drawer open on top of the freshly created page, so the
+      // editor stays hidden behind the tree. Close it here so the new page opens
+      // in the editor — mirrors the row-click drawer-close in space-tree-row.
+      // No-op on desktop, where the mobile drawer atom is already false.
+      setMobileSidebar(false);
    },
-    [spaceId, createPageMutation, setData, store, navigate, spaceSlug],
+    [
+      spaceId,
+      createPageMutation,
+      setData,
+      store,
+      navigate,
+      spaceSlug,
+      setMobileSidebar,
+    ],
  );

  const handleRename = useCallback(