diff --git a/apps/client/package.json b/apps/client/package.json
index 76d617da..709bc01b 100644
--- a/apps/client/package.json
+++ b/apps/client/package.json
@@ -13,6 +13,7 @@
   },
   "dependencies": {
     "@ai-sdk/react": "^3.0.208",
+    "@braintree/sanitize-url": "7.1.2",
     "@atlaskit/pragmatic-drag-and-drop": "1.8.1",
     "@atlaskit/pragmatic-drag-and-drop-auto-scroll": "2.1.5",
     "@atlaskit/pragmatic-drag-and-drop-flourish": "2.0.15",
diff --git a/apps/client/src/App.tsx b/apps/client/src/App.tsx
index d19bbded..880bab00 100644
--- a/apps/client/src/App.tsx
+++ b/apps/client/src/App.tsx
@@ -1,38 +1,72 @@
+import { lazy, Suspense } from "react";
 import { Navigate, Route, Routes } from "react-router-dom";
+import { Center, Loader } from "@mantine/core";
+import { Error404 } from "@/components/ui/error-404.tsx";
+import Layout from "@/components/layouts/global/layout.tsx";
+import { useTrackOrigin } from "@/hooks/use-track-origin";
+
+// ShareLayout is route-split: its ShareShell chrome pulls in the table of
+// contents (and thus TipTap), so keeping it out of the eager graph removes the
+// editor engine from startup for authenticated users too.
+const ShareLayout = lazy(
+  () => import("@/features/share/components/share-layout.tsx"),
+);
+
+// Auth / entry pages stay eager: they are the first paint for an unauthenticated
+// visitor (e.g. /login) and are already small, so code-splitting them would only
+// add a cold-chunk round trip to the most common cold-start path.
 import SetupWorkspace from "@/pages/auth/setup-workspace.tsx";
 import LoginPage from "@/pages/auth/login";
-import Home from "@/pages/dashboard/home";
-import Page from "@/pages/page/page";
-import AccountSettings from "@/pages/settings/account/account-settings";
-import WorkspaceMembers from "@/pages/settings/workspace/workspace-members";
-import WorkspaceSettings from "@/pages/settings/workspace/workspace-settings";
-import AiSettings from "@/pages/settings/workspace/ai-settings";
-import Groups from "@/pages/settings/group/groups";
-import GroupInfo from "./pages/settings/group/group-info";
-import Spaces from "@/pages/settings/space/spaces.tsx";
-import { Error404 } from "@/components/ui/error-404.tsx";
-import AccountPreferences from "@/pages/settings/account/account-preferences.tsx";
-import SpaceHome from "@/pages/space/space-home.tsx";
-import PageRedirect from "@/pages/page/page-redirect.tsx";
-import Layout from "@/components/layouts/global/layout.tsx";
 import InviteSignup from "@/pages/auth/invite-signup.tsx";
 import ForgotPassword from "@/pages/auth/forgot-password.tsx";
 import PasswordReset from "./pages/auth/password-reset";
-import SharedPage from "@/pages/share/shared-page.tsx";
-import Shares from "@/pages/settings/shares/shares.tsx";
-import ShareLayout from "@/features/share/components/share-layout.tsx";
+import PageRedirect from "@/pages/page/page-redirect.tsx";
 import ShareRedirect from "@/pages/share/share-redirect.tsx";
-import { useTrackOrigin } from "@/hooks/use-track-origin";
-import SpacesPage from "@/pages/spaces/spaces.tsx";
-import SpaceTrash from "@/pages/space/space-trash.tsx";
-import FavoritesPage from "@/pages/favorites/favorites-page";
-import LabelPage from "@/pages/label/label-page";
+
+// Heavy / leaf pages are route-split with React.lazy so their code (most
+// importantly the whole TipTap editor + KaTeX + lowlight grammars + drawio that
+// the page editor and the readonly share editor pull in) is fetched only when
+// the matching route is actually visited. The <Suspense> boundaries live inside
+// each Layout (around its <Outlet/>), so the app shell stays mounted while a
+// route chunk loads.
+const Home = lazy(() => import("@/pages/dashboard/home"));
+const Page = lazy(() => import("@/pages/page/page"));
+const SpaceHome = lazy(() => import("@/pages/space/space-home.tsx"));
+const SpaceTrash = lazy(() => import("@/pages/space/space-trash.tsx"));
+const SpacesPage = lazy(() => import("@/pages/spaces/spaces.tsx"));
+const FavoritesPage = lazy(() => import("@/pages/favorites/favorites-page"));
+const LabelPage = lazy(() => import("@/pages/label/label-page"));
+const SharedPage = lazy(() => import("@/pages/share/shared-page.tsx"));
+
+const AccountSettings = lazy(
+  () => import("@/pages/settings/account/account-settings"),
+);
+const AccountPreferences = lazy(
+  () => import("@/pages/settings/account/account-preferences.tsx"),
+);
+const WorkspaceSettings = lazy(
+  () => import("@/pages/settings/workspace/workspace-settings"),
+);
+const AiSettings = lazy(() => import("@/pages/settings/workspace/ai-settings"));
+const WorkspaceMembers = lazy(
+  () => import("@/pages/settings/workspace/workspace-members"),
+);
+const Groups = lazy(() => import("@/pages/settings/group/groups"));
+const GroupInfo = lazy(() => import("./pages/settings/group/group-info"));
+const Spaces = lazy(() => import("@/pages/settings/space/spaces.tsx"));
+const Shares = lazy(() => import("@/pages/settings/shares/shares.tsx"));
 
 export default function App() {
   useTrackOrigin();
 
   return (
-    <>
+    <Suspense
+      fallback={
+        <Center h="100vh">
+          <Loader size="sm" />
+        </Center>
+      }
+    >
       <Routes>
         <Route index element={<Navigate to="/home" />} />
         <Route path={"/login"} element={<LoginPage />} />
@@ -83,6 +117,6 @@ export default function App() {
 
         <Route path="*" element={<Error404 />} />
       </Routes>
-    </>
+    </Suspense>
   );
 }
diff --git a/apps/client/src/components/layouts/global/global-app-shell.tsx b/apps/client/src/components/layouts/global/global-app-shell.tsx
index 1b41011e..302cf2bc 100644
--- a/apps/client/src/components/layouts/global/global-app-shell.tsx
+++ b/apps/client/src/components/layouts/global/global-app-shell.tsx
@@ -1,9 +1,10 @@
 import { AppShell, Container } from "@mantine/core";
-import React, { useEffect, useRef, useState } from "react";
+import React, { Suspense, useEffect, useRef, useState } from "react";
 import { useLocation } from "react-router-dom";
 import { useTranslation } from "react-i18next";
 import SettingsSidebar from "@/components/settings/settings-sidebar.tsx";
-import { useAtom } from "jotai";
+import { useAtom, useAtomValue } from "jotai";
+import { aiChatWindowOpenAtom } from "@/features/ai-chat/atoms/ai-chat-atom.ts";
 import {
   APP_NAVBAR_ID,
   NAVBAR_COLLAPSE_BREAKPOINT,
@@ -14,8 +15,6 @@ import {
 } from "@/components/layouts/global/hooks/atoms/sidebar-atom.ts";
 import { SpaceSidebar } from "@/features/space/components/sidebar/space-sidebar.tsx";
 import { AppHeader } from "@/components/layouts/global/app-header.tsx";
-import Aside from "@/components/layouts/global/aside.tsx";
-import AiChatWindow from "@/features/ai-chat/components/ai-chat-window.tsx";
 import GitmostGlobalBridge from "@/features/editor/gitmost/gitmost-global-bridge.tsx";
 import classes from "./app-shell.module.css";
 import { useToggleSidebar } from "@/components/layouts/global/hooks/hooks/use-toggle-sidebar.ts";
@@ -23,6 +22,21 @@ import GlobalSidebar from "@/components/layouts/global/global-sidebar.tsx";
 import { ASIDE_PANEL_ID } from "@/hooks/use-toggle-aside.tsx";
 import { MAIN_CONTENT_ID, SkipToMain } from "@/components/ui/skip-to-main.tsx";
 
+// Lazily load the AI chat window so the AI SDK runtime it pulls in is fetched
+// only after the user first opens the chat, instead of for every authenticated
+// user on load. The window itself renders null while closed, so there is no
+// behavior difference — it simply is not mounted until first opened.
+const AiChatWindow = React.lazy(
+  () => import("@/features/ai-chat/components/ai-chat-window.tsx"),
+);
+
+// The right aside hosts the comment panel and table of contents, both of which
+// pull in TipTap. It only ever renders on page routes, so lazy-loading it keeps
+// the whole editor engine out of the eager global-shell startup graph.
+const Aside = React.lazy(
+  () => import("@/components/layouts/global/aside.tsx"),
+);
+
 export default function GlobalAppShell({
   children,
 }: {
@@ -37,6 +51,15 @@ export default function GlobalAppShell({
   const [isResizing, setIsResizing] = useState(false);
   const sidebarRef = useRef(null);
 
+  // Latch: once the AI chat window has been opened, keep it mounted so an
+  // in-flight stream is never torn down. Before the first open the AI chat chunk
+  // is never fetched.
+  const aiChatOpen = useAtomValue(aiChatWindowOpenAtom);
+  const [aiChatEverOpened, setAiChatEverOpened] = useState(false);
+  useEffect(() => {
+    if (aiChatOpen) setAiChatEverOpened(true);
+  }, [aiChatOpen]);
+
   const startResizing = React.useCallback((mouseDownEvent) => {
     mouseDownEvent.preventDefault();
     setIsResizing(true);
@@ -160,13 +183,21 @@ export default function GlobalAppShell({
                   : undefined
           }
         >
-          <Aside />
+          <Suspense fallback={null}>
+            <Aside />
+          </Suspense>
         </AppShell.Aside>
       )}
     </AppShell>
-    {/* Floating AI chat window. Mounted once globally; it is position: fixed
-        and self-hides when closed, so its place in the tree is not critical. */}
-    <AiChatWindow />
+    {/* Floating AI chat window. Mounted once globally on first open; it is
+        position: fixed and self-hides when closed, so its place in the tree is
+        not critical. Kept mounted after the first open so a live stream is not
+        aborted. */}
+    {aiChatEverOpened && (
+      <Suspense fallback={null}>
+        <AiChatWindow />
+      </Suspense>
+    )}
       {/* Global gitmost native bridge: registers listSpaces / listPages /
           createPageWithRecording on window.gitmost so the native host can
           create a page with a recording even when no page editor is open. */}
diff --git a/apps/client/src/components/layouts/global/layout.tsx b/apps/client/src/components/layouts/global/layout.tsx
index 4648de15..9e931c1f 100644
--- a/apps/client/src/components/layouts/global/layout.tsx
+++ b/apps/client/src/components/layouts/global/layout.tsx
@@ -1,5 +1,7 @@
+import { Suspense, useEffect } from "react";
 import { UserProvider } from "@/features/user/user-provider.tsx";
 import { Outlet, useParams } from "react-router-dom";
+import { Center, Loader } from "@mantine/core";
 import GlobalAppShell from "@/components/layouts/global/global-app-shell.tsx";
 import { SearchSpotlight } from "@/features/search/components/search-spotlight.tsx";
 import { useGetSpaceBySlugQuery } from "@/features/space/queries/space-query.ts";
@@ -8,10 +10,37 @@ export default function Layout() {
   const { spaceSlug } = useParams();
   const { data: space } = useGetSpaceBySlugQuery(spaceSlug);
 
+  // Warm the (now route-split) editor chunk during idle time on authenticated
+  // routes, so the first navigation to a page renders from cache instead of a
+  // cold chunk fetch. Best-effort: gated on requestIdleCallback and never blocks
+  // startup — the dynamic import mirrors the App.tsx route lazy loader so both
+  // resolve to the same chunk.
+  useEffect(() => {
+    const ric =
+      typeof window !== "undefined" && (window as any).requestIdleCallback;
+    const warm = () => {
+      void import("@/pages/page/page");
+    };
+    if (ric) {
+      const id = ric(warm);
+      return () => (window as any).cancelIdleCallback?.(id);
+    }
+    const timer = setTimeout(warm, 2000);
+    return () => clearTimeout(timer);
+  }, []);
+
   return (
     <UserProvider>
       <GlobalAppShell>
-        <Outlet />
+        <Suspense
+          fallback={
+            <Center h="60vh">
+              <Loader size="sm" />
+            </Center>
+          }
+        >
+          <Outlet />
+        </Suspense>
       </GlobalAppShell>
       <SearchSpotlight spaceId={space?.id} />
     </UserProvider>
diff --git a/apps/client/src/features/editor/atoms/editor-atoms.ts b/apps/client/src/features/editor/atoms/editor-atoms.ts
index 605a71db..d39a2395 100644
--- a/apps/client/src/features/editor/atoms/editor-atoms.ts
+++ b/apps/client/src/features/editor/atoms/editor-atoms.ts
@@ -1,5 +1,8 @@
 import { atom } from "jotai";
-import { Editor } from "@tiptap/core";
+// Type-only: these atoms only hold an Editor reference for typing. A value
+// import would drag the whole @tiptap/core engine into the eager graph of every
+// shell component that reads one of these atoms.
+import type { Editor } from "@tiptap/core";
 import { PageEditMode } from "@/features/user/types/user.types.ts";
 import type { DictationUnavailableReason } from "@/features/dictation/dictation-status";
 
diff --git a/apps/client/src/features/editor/components/drawio/drawio-menu-lazy.tsx b/apps/client/src/features/editor/components/drawio/drawio-menu-lazy.tsx
new file mode 100644
index 00000000..52b66168
--- /dev/null
+++ b/apps/client/src/features/editor/components/drawio/drawio-menu-lazy.tsx
@@ -0,0 +1,16 @@
+import { lazy, Suspense } from "react";
+import { EditorMenuProps } from "@/features/editor/components/table/types/types.ts";
+
+// Lazily load the drawio bubble menu so it is split out of the editor chunk and
+// fetched only when an editable editor is mounted (mirrors excalidraw-menu-lazy).
+const DrawioMenu = lazy(
+  () => import("@/features/editor/components/drawio/drawio-menu.tsx"),
+);
+
+export default function DrawioMenuLazy(props: EditorMenuProps) {
+  return (
+    <Suspense fallback={null}>
+      <DrawioMenu {...props} />
+    </Suspense>
+  );
+}
diff --git a/apps/client/src/features/editor/components/drawio/drawio-view-lazy.tsx b/apps/client/src/features/editor/components/drawio/drawio-view-lazy.tsx
new file mode 100644
index 00000000..bb45fa72
--- /dev/null
+++ b/apps/client/src/features/editor/components/drawio/drawio-view-lazy.tsx
@@ -0,0 +1,17 @@
+import { lazy, Suspense } from "react";
+import { NodeViewProps } from "@tiptap/react";
+
+// Lazily load the drawio node view so the heavy react-drawio embed runtime is
+// split into its own chunk and fetched only when a drawio diagram is actually
+// rendered (mirrors excalidraw-view-lazy).
+const DrawioView = lazy(
+  () => import("@/features/editor/components/drawio/drawio-view.tsx"),
+);
+
+export default function DrawioViewLazy(props: NodeViewProps) {
+  return (
+    <Suspense fallback={null}>
+      <DrawioView {...props} />
+    </Suspense>
+  );
+}
diff --git a/apps/client/src/features/editor/components/math/math-block-lazy.tsx b/apps/client/src/features/editor/components/math/math-block-lazy.tsx
new file mode 100644
index 00000000..0ae1d360
--- /dev/null
+++ b/apps/client/src/features/editor/components/math/math-block-lazy.tsx
@@ -0,0 +1,19 @@
+import { lazy, Suspense } from "react";
+import { NodeViewProps } from "@tiptap/react";
+
+// Lazily load the KaTeX-backed block math view so the katex chunk is fetched
+// only when a document actually contains a math node (mirrors the mermaid/
+// excalidraw lazy pattern). The local Suspense keeps a slow katex chunk from
+// crashing or blocking the whole editor: while it loads we render the raw
+// LaTeX source as a node-sized placeholder.
+const MathBlockView = lazy(
+  () => import("@/features/editor/components/math/math-block.tsx"),
+);
+
+export default function MathBlockViewLazy(props: NodeViewProps) {
+  return (
+    <Suspense fallback={<div data-katex="true">{props.node.attrs.text}</div>}>
+      <MathBlockView {...props} />
+    </Suspense>
+  );
+}
diff --git a/apps/client/src/features/editor/components/math/math-inline-lazy.tsx b/apps/client/src/features/editor/components/math/math-inline-lazy.tsx
new file mode 100644
index 00000000..14b157fe
--- /dev/null
+++ b/apps/client/src/features/editor/components/math/math-inline-lazy.tsx
@@ -0,0 +1,19 @@
+import { lazy, Suspense } from "react";
+import { NodeViewProps } from "@tiptap/react";
+
+// Lazily load the KaTeX-backed inline math view so the katex chunk is fetched
+// only when a document actually contains a math node (mirrors the mermaid/
+// excalidraw lazy pattern). The local Suspense keeps a slow katex chunk from
+// crashing or blocking the whole editor: while it loads we render the raw
+// LaTeX source as a node-sized placeholder.
+const MathInlineView = lazy(
+  () => import("@/features/editor/components/math/math-inline.tsx"),
+);
+
+export default function MathInlineViewLazy(props: NodeViewProps) {
+  return (
+    <Suspense fallback={<span data-katex="true">{props.node.attrs.text}</span>}>
+      <MathInlineView {...props} />
+    </Suspense>
+  );
+}
diff --git a/apps/client/src/features/editor/extensions/extensions.ts b/apps/client/src/features/editor/extensions/extensions.ts
index 4232307c..829d32c9 100644
--- a/apps/client/src/features/editor/extensions/extensions.ts
+++ b/apps/client/src/features/editor/extensions/extensions.ts
@@ -81,8 +81,8 @@ import {
   createResizeHandle,
   buildResizeClasses,
 } from "@/features/editor/components/common/node-resize-handles.ts";
-import MathInlineView from "@/features/editor/components/math/math-inline.tsx";
-import MathBlockView from "@/features/editor/components/math/math-block.tsx";
+import MathInlineView from "@/features/editor/components/math/math-inline-lazy.tsx";
+import MathBlockView from "@/features/editor/components/math/math-block-lazy.tsx";
 import ImageView from "@/features/editor/components/image/image-view.tsx";
 import CalloutView from "@/features/editor/components/callout/callout-view.tsx";
 import StatusView from "@/features/editor/components/status/status-view.tsx";
@@ -90,7 +90,7 @@ import VideoView from "@/features/editor/components/video/video-view.tsx";
 import AudioView from "@/features/editor/components/audio/audio-view.tsx";
 import AttachmentView from "@/features/editor/components/attachment/attachment-view.tsx";
 import CodeBlockView from "@/features/editor/components/code-block/code-block-view.tsx";
-import DrawioView from "../components/drawio/drawio-view";
+import DrawioView from "../components/drawio/drawio-view-lazy.tsx";
 import ExcalidrawView from "@/features/editor/components/excalidraw/excalidraw-view-lazy.tsx";
 import EmbedView from "@/features/editor/components/embed/embed-view.tsx";
 import HtmlEmbedView from "@/features/editor/components/html-embed/html-embed-view.tsx";
diff --git a/apps/client/src/features/editor/gitmost/gitmost-global-bridge.tsx b/apps/client/src/features/editor/gitmost/gitmost-global-bridge.tsx
index a1bef61f..d0fa54ba 100644
--- a/apps/client/src/features/editor/gitmost/gitmost-global-bridge.tsx
+++ b/apps/client/src/features/editor/gitmost/gitmost-global-bridge.tsx
@@ -1,8 +1,17 @@
 import { useEffect, useRef } from "react";
 import { useNavigate } from "react-router-dom";
 import { getDefaultStore } from "jotai";
-import { WebSocketStatus } from "@hocuspocus/provider";
-import { Editor } from "@tiptap/core";
+
+// Literal value of WebSocketStatus.Connected from @hocuspocus/provider. Inlined
+// so this always-mounted global bridge does not statically import
+// @hocuspocus/provider — that import pulls Yjs (and, through a shared chunk, the
+// whole TipTap engine) into the eager startup graph. yjsConnectionStatusAtom
+// already stores these raw status strings.
+const YJS_STATUS_CONNECTED = "connected";
+// Type-only: importing Editor as a type keeps @tiptap/core (the whole editor
+// engine) out of the eager global-shell graph — the bridge only uses it for
+// annotations/casts, never as a runtime value.
+import type { Editor } from "@tiptap/core";
 import {
   pageEditorAtom,
   yjsConnectionStatusAtom,
@@ -16,15 +25,19 @@ import {
   getSidebarPages,
 } from "@/features/page/services/page-service.ts";
 import { buildPageUrl } from "@/features/page/page.utils.ts";
-import {
+// Types are erased at build time, so importing them does not pull the module's
+// runtime (which drags in @tiptap + the editor-ext barrel). The actual recording
+// helpers are dynamically imported at call time inside createPageWithRecording,
+// keeping the editor engine out of the eager global-shell startup graph — the
+// bridge is mounted for every authenticated user but recording is a rare,
+// native-host-driven action.
+import type {
   GitmostBridge,
   GitmostCreatePagePayload,
   GitmostCreatePageResult,
   GitmostListPagesPayload,
   GitmostListPagesResult,
   GitmostListSpacesResult,
-  gitmostDecodePayloadToFile,
-  gitmostUploadFileToEditor,
 } from "@/features/editor/gitmost/gitmost-recording.ts";
 
 // How long to wait for a freshly-navigated page's editor to mount, become
@@ -57,7 +70,7 @@ function gitmostWaitForEditor(
         !editor.isDestroyed &&
         editor.isEditable &&
         editorPageId === pageId &&
-        yjsStatus === WebSocketStatus.Connected;
+        yjsStatus === YJS_STATUS_CONNECTED;
       if (ready) {
         resolve(editor);
         return;
@@ -171,6 +184,12 @@ export default function GitmostGlobalBridge() {
           };
         }
 
+        // Load the recording helpers on demand (see the import note above). This
+        // is the only place they are needed, so the @tiptap/editor-ext code they
+        // pull in stays out of the eager startup graph.
+        const { gitmostDecodePayloadToFile, gitmostUploadFileToEditor } =
+          await import("@/features/editor/gitmost/gitmost-recording.ts");
+
         // Validate/decode the recording BEFORE creating the page so a bad
         // payload never leaves an empty junk page behind. Per the createPage
         // error contract, any decode failure collapses to "insert-failed" (the
diff --git a/apps/client/src/features/editor/page-editor.tsx b/apps/client/src/features/editor/page-editor.tsx
index 9953d6c5..b5a6221f 100644
--- a/apps/client/src/features/editor/page-editor.tsx
+++ b/apps/client/src/features/editor/page-editor.tsx
@@ -59,7 +59,7 @@ import {
   handlePaste,
 } from "@/features/editor/components/common/editor-paste-handler.tsx";
 import ExcalidrawMenu from "./components/excalidraw/excalidraw-menu-lazy";
-import DrawioMenu from "./components/drawio/drawio-menu";
+import DrawioMenu from "./components/drawio/drawio-menu-lazy";
 import { useCollabToken } from "@/features/auth/queries/auth-query.tsx";
 import SearchAndReplaceDialog from "@/features/editor/components/search-and-replace/search-and-replace-dialog.tsx";
 import { useDebouncedCallback, useDocumentVisibility } from "@mantine/hooks";
diff --git a/apps/client/src/features/share/components/share-layout.tsx b/apps/client/src/features/share/components/share-layout.tsx
index e3b2eb17..b277fe45 100644
--- a/apps/client/src/features/share/components/share-layout.tsx
+++ b/apps/client/src/features/share/components/share-layout.tsx
@@ -1,10 +1,20 @@
+import { Suspense } from "react";
 import { Outlet } from "react-router-dom";
+import { Center, Loader } from "@mantine/core";
 import ShareShell from "@/features/share/components/share-shell.tsx";
 
 export default function ShareLayout() {
   return (
     <ShareShell>
-      <Outlet />
+      <Suspense
+        fallback={
+          <Center h="60vh">
+            <Loader size="sm" />
+          </Center>
+        }
+      >
+        <Outlet />
+      </Suspense>
     </ShareShell>
   );
 }
diff --git a/apps/client/src/hooks/use-clipboard.ts b/apps/client/src/hooks/use-clipboard.ts
index e68a92ba..7371f88e 100644
--- a/apps/client/src/hooks/use-clipboard.ts
+++ b/apps/client/src/hooks/use-clipboard.ts
@@ -1,7 +1,7 @@
 // Source: https://github.com/mantinedev/mantine/blob/master/packages/@mantine/hooks/src/use-clipboard/use-clipboard.ts
 // polyfilled to support execCommand fallback
 import { useState } from "react";
-import { execCommandCopy } from "@docmost/editor-ext";
+import { execCommandCopy } from "@/lib/copy-to-clipboard.ts";
 
 export type UseClipboardOptions = {
   timeout?: number;
diff --git a/apps/client/src/lib/config.ts b/apps/client/src/lib/config.ts
index adc5615d..1b270cdd 100644
--- a/apps/client/src/lib/config.ts
+++ b/apps/client/src/lib/config.ts
@@ -1,7 +1,7 @@
 import bytes from "bytes";
 import { castToBoolean } from "@/lib/utils.tsx";
 import { AvatarIconType } from "@/features/attachments/types/attachment.types.ts";
-import { sanitizeUrl } from "@docmost/editor-ext";
+import { sanitizeUrl } from "@/lib/sanitize-url.ts";
 
 declare global {
   interface Window {
diff --git a/apps/client/src/lib/copy-to-clipboard.ts b/apps/client/src/lib/copy-to-clipboard.ts
new file mode 100644
index 00000000..e30de66e
--- /dev/null
+++ b/apps/client/src/lib/copy-to-clipboard.ts
@@ -0,0 +1,16 @@
+// Client-local execCommand copy fallback (previously imported from
+// @docmost/editor-ext). It lives here so the ubiquitous useClipboard / CopyButton
+// path does not pull in the editor-ext barrel — and with it the whole TipTap
+// engine — through the eager startup graph. Behavior is identical to the
+// editor-ext helper it replaces.
+export function execCommandCopy(text: string): void {
+  const textarea = document.createElement("textarea");
+  textarea.value = text;
+  textarea.style.position = "fixed";
+  textarea.style.left = "-9999px";
+  textarea.style.top = "-9999px";
+  document.body.appendChild(textarea);
+  textarea.select();
+  document.execCommand("copy");
+  document.body.removeChild(textarea);
+}
diff --git a/apps/client/src/lib/sanitize-url.ts b/apps/client/src/lib/sanitize-url.ts
new file mode 100644
index 00000000..3c48e8d2
--- /dev/null
+++ b/apps/client/src/lib/sanitize-url.ts
@@ -0,0 +1,15 @@
+import { sanitizeUrl as braintreeSanitizeUrl } from "@braintree/sanitize-url";
+
+// Client-local copy of editor-ext's sanitizeUrl wrapper. Importing it from the
+// editor-ext barrel dragged the whole TipTap engine into the eager startup graph
+// via the app-wide config module (getFileUrl). This keeps the exact same
+// behavior (braintree sanitize + normalize "about:blank" -> "") without that
+// dependency.
+export function sanitizeUrl(url: string | undefined): string {
+  if (!url) return "";
+
+  const sanitized = braintreeSanitizeUrl(url);
+
+  // Return an empty string instead of "about:blank".
+  return sanitized === "about:blank" ? "" : sanitized;
+}
diff --git a/apps/client/src/main.tsx b/apps/client/src/main.tsx
index 5dbf6b81..6efaf778 100644
--- a/apps/client/src/main.tsx
+++ b/apps/client/src/main.tsx
@@ -4,6 +4,7 @@ import "@mantine/notifications/styles.css";
 import '@mantine/dates/styles.css';
 import "@/styles/a11y-overrides.css";
 
+import { ReactNode } from "react";
 import ReactDOM from "react-dom/client";
 import App from "./App.tsx";
 import { mantineCssResolver, theme } from "@/theme";
@@ -14,14 +15,12 @@ import { Notifications } from "@mantine/notifications";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import { HelmetProvider } from "react-helmet-async";
 import "./i18n";
-import { PostHogProvider } from "posthog-js/react";
 import {
   getPostHogHost,
   getPostHogKey,
   isCloud,
   isPostHogEnabled,
 } from "@/lib/config.ts";
-import posthog from "posthog-js";
 
 export const queryClient = new QueryClient({
   defaultOptions: {
@@ -34,31 +33,46 @@ export const queryClient = new QueryClient({
   },
 });
 
-if (isCloud() && isPostHogEnabled) {
-  posthog.init(getPostHogKey(), {
-    api_host: getPostHogHost(),
-    defaults: "2025-05-24",
-    disable_session_recording: true,
-    capture_pageleave: false,
-  });
-}
-
 const container = document.getElementById("root") as HTMLElement;
 const root = (container as any).__reactRoot ??= ReactDOM.createRoot(container);
 
-root.render(
-  <BrowserRouter>
-    <MantineProvider theme={theme} cssVariablesResolver={mantineCssResolver}>
-      <ModalsProvider>
-        <QueryClientProvider client={queryClient}>
-          <Notifications position="bottom-center" limit={3} zIndex={10000} />
-          <HelmetProvider>
-            <PostHogProvider client={posthog}>
-              <App />
-            </PostHogProvider>
-          </HelmetProvider>
-        </QueryClientProvider>
-      </ModalsProvider>
-    </MantineProvider>
-  </BrowserRouter>,
-);
+function renderApp(app: ReactNode) {
+  root.render(
+    <BrowserRouter>
+      <MantineProvider theme={theme} cssVariablesResolver={mantineCssResolver}>
+        <ModalsProvider>
+          <QueryClientProvider client={queryClient}>
+            <Notifications position="bottom-center" limit={3} zIndex={10000} />
+            <HelmetProvider>{app}</HelmetProvider>
+          </QueryClientProvider>
+        </ModalsProvider>
+      </MantineProvider>
+    </BrowserRouter>,
+  );
+}
+
+async function bootstrap() {
+  // posthog-js (and its React provider) is only pulled in for cloud deployments
+  // with analytics enabled, so self-hosted builds never download it. The gate is
+  // kept identical to the previous eager code so cloud analytics behavior is
+  // unchanged; the import is simply deferred behind it.
+  if (isCloud() && isPostHogEnabled) {
+    const { default: posthog } = await import("posthog-js");
+    const { PostHogProvider } = await import("posthog-js/react");
+    posthog.init(getPostHogKey(), {
+      api_host: getPostHogHost(),
+      defaults: "2025-05-24",
+      disable_session_recording: true,
+      capture_pageleave: false,
+    });
+    renderApp(
+      <PostHogProvider client={posthog}>
+        <App />
+      </PostHogProvider>,
+    );
+  } else {
+    renderApp(<App />);
+  }
+}
+
+void bootstrap();
diff --git a/apps/client/vite.config.ts b/apps/client/vite.config.ts
index 8b9994ce..e565212f 100644
--- a/apps/client/vite.config.ts
+++ b/apps/client/vite.config.ts
@@ -63,6 +63,20 @@ export default defineConfig(({ mode }) => {
                 name: "vendor-mantine",
                 test: /[\\/]node_modules[\\/]@mantine[\\/]/,
               },
+              // NOTE: TipTap/ProseMirror/Yjs are intentionally NOT force-grouped
+              // into a single vendor chunk. Doing so backfires: rolldown co-locates
+              // a small module shared with the (eager) react-i18next runtime into
+              // that group chunk, which then drags the whole ~590KB editor engine
+              // into the eager modulepreload graph. Left to the default splitting,
+              // the editor engine stays in lazily-loaded chunks pulled only by the
+              // route-split editor/share pages. KaTeX is safe to group (nothing
+              // eager references it).
+              // KaTeX in its own stable chunk; loaded on demand by the lazy math
+              // node views (never in the startup path).
+              {
+                name: "vendor-katex",
+                test: /[\\/]node_modules[\\/]katex[\\/]/,
+              },
             ],
           },
         },
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 299f5e51..3b4e37a8 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -269,6 +269,9 @@ importers:
       '@atlaskit/pragmatic-drag-and-drop-live-region':
         specifier: 1.3.4
         version: 1.3.4
+      '@braintree/sanitize-url':
+        specifier: 7.1.2
+        version: 7.1.2
       '@casl/react':
         specifier: 5.0.1
         version: 5.0.1(@casl/ability@6.8.0)(react@18.3.1)
@@ -16153,7 +16156,7 @@ snapshots:
       obug: 2.1.1
       std-env: 4.1.0
       tinyrainbow: 3.1.0
-      vitest: 4.1.6(@opentelemetry/api@1.9.0)(@types/node@25.5.0)(@vitest/coverage-v8@4.1.6)(happy-dom@20.8.9)(jsdom@27.4.0(@noble/hashes@2.0.1))(vite@8.0.5(@types/node@25.5.0)(esbuild@0.28.0)(jiti@2.4.2)(less@4.2.0)(sugarss@5.0.1(postcss@8.5.14))(terser@5.39.0)(tsx@4.21.0)(yaml@2.8.3))
+      vitest: 4.1.6(@opentelemetry/api@1.9.0)(@types/node@22.19.1)(@vitest/coverage-v8@4.1.6)(happy-dom@20.8.9)(jsdom@25.0.0)(vite@8.0.5(@types/node@22.19.1)(esbuild@0.28.0)(jiti@2.4.2)(less@4.2.0)(sugarss@5.0.1(postcss@8.5.14))(terser@5.39.0)(tsx@4.21.0)(yaml@2.8.3))
 
   '@vitest/expect@4.1.6':
     dependencies: