fix(room-nav): drop pointless dynamic import of setRoomNotificationPreference

RoomNavItem.tsx already statically imported getRoomNotificationModeIcon
and RoomNotificationMode from the same module, so the two
`await import('../../hooks/useRoomsNotificationPreferences')` calls
(in unmuteRoom and handleMuteFor) never achieved real code-splitting —
verified by building and grepping dist/assets: setRoomNotificationPreference
landed in the same eager entry chunk regardless, since Rolldown can't
split a module already reachable via a static import elsewhere. Just
import it statically alongside its siblings instead. No behavior
change — confirmed via 3 independent investigations before starting
and 3 independent reviews of this diff before committing.

Closes LotusGuild/cinny#5

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/features/room-nav/RoomNavItem.tsx

@@ -66,6 +66,7 @@ import { useSpaceOptionally } from '../../hooks/useSpace';
 import {
   getRoomNotificationModeIcon,
   RoomNotificationMode,
+  setRoomNotificationPreference,
 } from '../../hooks/useRoomsNotificationPreferences';
 import { RoomNotificationModeSwitcher } from '../../components/RoomNotificationSwitcher';
 import { getRoomCreatorsForRoomId, useRoomCreators } from '../../hooks/useRoomCreators';
@@ -298,8 +299,6 @@ export function saveMuteTimers(timers: MuteTimerEntry[]): void {
 // Reverse a timed mute: restore the room's notification mode to Unset and drop
 // its persisted timer. Shared by the in-session timer and the boot-time restore.
 export async function unmuteRoom(mx: MatrixClient, roomId: string): Promise<void> {
-  const { setRoomNotificationPreference } =
-    await import('../../hooks/useRoomsNotificationPreferences');
   await setRoomNotificationPreference(
     mx,
     roomId,
@@ -392,8 +391,6 @@ const RoomNavItemMenu = forwardRef<HTMLDivElement, RoomNavItemMenuProps>(
 
     const handleMuteFor = useCallback(
       async (durationMs: number | null) => {
-        const { setRoomNotificationPreference } =
-          await import('../../hooks/useRoomsNotificationPreferences');
         const prevMode = notificationMode ?? RoomNotificationMode.Unset;
         await setRoomNotificationPreference(
           mx,