perf: split chunks and lazy-load Room to shrink initial bundle

manualChunks: add sentry, folds, i18n, jotai, immer
Router: lazy-load Room component (used in home/direct/space routes)
Sentry: wire in real DSN with browserTracingIntegration, 5% trace rate,
  tracePropagationTargets scoped to matrix.lotusguild.org, sendDefaultPii=false

Main bundle: 2481 kB -> 1857 kB gzip 623 kB -> 450 kB (-28% initial load)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/pages/Router.tsx

@@ -49,7 +49,7 @@ import { RouteSpaceProvider, Space, SpaceRouteRoomProvider, SpaceSearch } from '
 
 
 import { setAfterLoginRedirectPath } from './afterLoginRedirectPath';
-import { Room } from '../features/room';
+const Room = React.lazy(() => import('../features/room').then(m => ({ default: m.Room })));
 
 import { WelcomePage } from './client/WelcomePage';
 import { SidebarNav } from './client/SidebarNav';
@@ -186,7 +186,9 @@ export const createRouter = (clientConfig: ClientConfig, screenSize: ScreenSize)
             path={_ROOM_PATH}
             element={
               <HomeRouteRoomProvider>
-                <Room />
+                <React.Suspense fallback={null}>
+                  <Room />
+                </React.Suspense>
               </HomeRouteRoomProvider>
             }
           />
@@ -211,7 +213,9 @@ export const createRouter = (clientConfig: ClientConfig, screenSize: ScreenSize)
             path={_ROOM_PATH}
             element={
               <DirectRouteRoomProvider>
-                <Room />
+                <React.Suspense fallback={null}>
+                  <Room />
+                </React.Suspense>
               </DirectRouteRoomProvider>
             }
           />
@@ -251,7 +255,9 @@ export const createRouter = (clientConfig: ClientConfig, screenSize: ScreenSize)
             path={_ROOM_PATH}
             element={
               <SpaceRouteRoomProvider>
-                <Room />
+                <React.Suspense fallback={null}>
+                  <Room />
+                </React.Suspense>
               </SpaceRouteRoomProvider>
             }
           />