test: cover features since 053a9c0d + repair test tooling

Add ~330 tests across server (Jest), client (Vitest), editor-ext (Vitest)
and packages/mcp (node:test) for the gitmost features added since
053a9c0d: AI chat, AI agent roles, public-share assistant, MCP per-user
auth, HTML embed, page templates/embed, realtime tree, tree
expand/collapse, and the AI-settings UI.

Test-tooling fixes (prerequisite, were silently hiding coverage):
- Repair 3 page-template specs broken by the 11-arg TransclusionService
  constructor; they never compiled, so template access-control / content
  -leak / unsync-strip coverage was fictitious.
- Build @docmost/editor-ext before server tests via a `pretest` hook;
  the stale dist omitted the new HtmlEmbed/PageEmbed exports (TS2305).
- Let jest resolve the .tsx email templates: add `tsx` to
  moduleFileExtensions and widen the ts-jest transform to (t|j)sx?.

Behaviour-preserving "extract pure core" refactors that the tests drive:
- server: resolveShareAssistantRequest + uiMessageTextLength
  (public-share controller), decideBasicGate + mapAuthResultToResponse
  (mcp), buildErrorAssistantRecord (ai-chat), jsonbObject export (roles).
- client: render-raw-html + shouldExecute/canEdit, decide-embed-state,
  page-embed picker utils, tree-socket reducers, open/close branch maps,
  isEndpointConfigured/resolveKeyField; buildTreeWithChildren now treats
  a permission-trimmed orphan as a root instead of crashing.

Deferred (need a test DB or HTTP harness, documented in the specs):
repo-level Postgres integration tests and the public-share XFF E2E.
Pre-existing DI/lib0-ESM suite failures are untouched and out of scope.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/client/src/features/websocket/tree-socket-reducers.ts

@@ -0,0 +1,164 @@
+import { SpaceTreeNode } from "@/features/page/tree/types.ts";
+import { treeModel } from "@/features/page/tree/model/tree-model";
+import type {
+  AddTreeNodeEvent,
+  MoveTreeNodeEvent,
+  DeleteTreeNodeEvent,
+  UpdateEvent,
+} from "@/features/websocket/types";
+
+// Pure tree transforms for the `useTreeSocket` reducer arms. Extracted from the
+// hook so the realtime tree behaviour can be unit-tested without rendering the
+// hook, the socket, or jotai. The hook calls these inside its `setData`.
+//
+// IMPORTANT: these are PURE — no `queryClient`, no notifications, no atoms. The
+// delete arm's `queryClient.invalidateQueries` side effect stays in the hook;
+// `applyDeleteTreeNode` is a pure tree transform only.
+
+// `updateOne` for a page: patch the in-tree node's name/icon from the payload.
+// No-op (returns the same reference) when the node isn't loaded on this client.
+export function applyUpdateOne(
+  prev: SpaceTreeNode[],
+  event: UpdateEvent,
+): SpaceTreeNode[] {
+  if (!treeModel.find(prev, event.id)) return prev;
+  let next = prev;
+  if (event.payload?.title !== undefined) {
+    next = treeModel.update(next, event.id, {
+      name: event.payload.title,
+    } as Partial<SpaceTreeNode>);
+  }
+  if (event.payload?.icon !== undefined) {
+    next = treeModel.update(next, event.id, {
+      icon: event.payload.icon,
+    } as Partial<SpaceTreeNode>);
+  }
+  return next;
+}
+
+// `addTreeNode`: insert the new node by its fractional `position` among the
+// already-loaded siblings (not the sender's absolute index). Idempotent — if the
+// id already exists (optimistic author insert or re-delivery) returns prev
+// unchanged. Flips the new parent's `hasChildren` to true so the chevron renders.
+export function applyAddTreeNode(
+  prev: SpaceTreeNode[],
+  payload: AddTreeNodeEvent["payload"],
+): SpaceTreeNode[] {
+  // Idempotent: the author already inserted the node optimistically, and a node
+  // may be re-delivered — never insert a duplicate id.
+  if (treeModel.find(prev, payload.data.id)) return prev;
+  const newParentId = payload.parentId as string | null;
+  // Insert by `position` among already-loaded siblings (not the sender's
+  // absolute index) so order is consistent across clients with different loaded
+  // sets.
+  let next = treeModel.insertByPosition(prev, newParentId, payload.data);
+  // Mirror the emitter: flip new parent's hasChildren to true so the chevron
+  // renders on the receiver.
+  if (newParentId) {
+    next = treeModel.update(next, newParentId, {
+      hasChildren: true,
+    } as Partial<SpaceTreeNode>);
+  }
+  return next;
+}
+
+// `moveTreeNode`: place the moved node by its fractional `position` among the new
+// siblings (NOT the sender's absolute index). If the destination parent isn't
+// loaded on this client, fall back to removing the source so the UI stays
+// consistent. Applies authoritative `pageData` fields and mirrors the
+// `hasChildren` bookkeeping for both the old and the new parent.
+export function applyMoveTreeNode(
+  prev: SpaceTreeNode[],
+  payload: MoveTreeNodeEvent["payload"],
+): SpaceTreeNode[] {
+  const sourceBefore = treeModel.find(prev, payload.id);
+  if (!sourceBefore) return prev;
+  const oldParentId = (sourceBefore as SpaceTreeNode).parentPageId ?? null;
+  const newParentId = payload.parentId as string | null;
+
+  // Place the node by its fractional `position` among the new siblings — NOT by
+  // the sender's absolute `index` (the sender computed that against its own
+  // loaded set, which differs from this receiver's). Using the position keeps
+  // the visible order correct on every client; placing at `index: 0` would
+  // wrongly drop reordered/moved nodes at the top of their new sibling list.
+  const placed = treeModel.placeByPosition(prev, payload.id, {
+    parentId: newParentId,
+    position: payload.position,
+  });
+  // `placeByPosition` silently returns the same reference if the destination
+  // parent isn't loaded on this client. Falling back to removing the source
+  // keeps the UI consistent (the source reappears when the user expands the new
+  // parent and lazy-load fetches it).
+  if (placed === prev) {
+    return treeModel.remove(prev, payload.id);
+  }
+
+  // Apply the authoritative node fields the move payload carries (`pageData`) so
+  // receivers don't keep a stale title/icon/chevron on the moved node.
+  // `placeByPosition` already set `position`.
+  const pageData = payload.pageData as
+    | {
+        title?: string | null;
+        icon?: string | null;
+        hasChildren?: boolean;
+      }
+    | undefined;
+  const patch: Partial<SpaceTreeNode> = {
+    position: payload.position,
+    // Honest type: a root move has a null parent, so this is `string | null`,
+    // not always `string`.
+    parentPageId: newParentId as string | null,
+  };
+  if (pageData) {
+    // The tree node stores the title as `name`.
+    if (pageData.title !== undefined) patch.name = pageData.title ?? "";
+    if (pageData.icon !== undefined) patch.icon = pageData.icon ?? undefined;
+    if (pageData.hasChildren !== undefined)
+      patch.hasChildren = pageData.hasChildren;
+  }
+  let next = treeModel.update(placed, payload.id, patch);
+
+  // Mirror the emitter's hasChildren bookkeeping so both clients converge to the
+  // same chevron state.
+  if (oldParentId) {
+    const oldParent = treeModel.find(next, oldParentId);
+    if (!oldParent?.children?.length) {
+      next = treeModel.update(next, oldParentId, {
+        hasChildren: false,
+      } as Partial<SpaceTreeNode>);
+    }
+  }
+  if (newParentId) {
+    next = treeModel.update(next, newParentId, {
+      hasChildren: true,
+    } as Partial<SpaceTreeNode>);
+  }
+
+  return next;
+}
+
+// `deleteTreeNode`: remove the node (and its descendants) from the tree.
+// Idempotent — if the node is already gone returns prev unchanged. Mirrors the
+// `hasChildren` bookkeeping: a parent left childless flips `hasChildren` false.
+//
+// PURE: the `queryClient.invalidateQueries` side effect lives in the hook, not
+// here.
+export function applyDeleteTreeNode(
+  prev: SpaceTreeNode[],
+  payload: DeleteTreeNodeEvent["payload"],
+): SpaceTreeNode[] {
+  if (!treeModel.find(prev, payload.node.id)) return prev;
+  let next = treeModel.remove(prev, payload.node.id);
+  // Mirror the emitter's hasChildren bookkeeping so both clients converge to the
+  // same chevron state when the last child is deleted.
+  const parentPageId = payload.node.parentPageId;
+  if (parentPageId) {
+    const parent = treeModel.find(next, parentPageId);
+    if (!parent?.children?.length) {
+      next = treeModel.update(next, parentPageId, {
+        hasChildren: false,
+      } as Partial<SpaceTreeNode>);
+    }
+  }
+  return next;
+}