chore: upgrade i18next 26, prettier 3, fontsource-variable, domhandler 6, lint-staged 17

- i18next 23->26 + react-i18next 15->17
- prettier 2->3, reformat all files
- replace @fontsource/inter with @fontsource-variable/inter 5, update import path
- domhandler 5->6 (aligns with transitive deps)
- lint-staged 16->17

src/app/components/RoomNotificationSwitcher.tsx

@@ -17,7 +17,7 @@ const useRoomNotificationModes = (): RoomNotificationMode[] =>
       RoomNotificationMode.SpecialMessages,
       RoomNotificationMode.Mute,
     ],
-    []
+    [],
   );
 
 const useRoomNotificationModeStr = (): Record<RoomNotificationMode, string> =>
@@ -28,7 +28,7 @@ const useRoomNotificationModeStr = (): Record<RoomNotificationMode, string> =>
       [RoomNotificationMode.SpecialMessages]: 'Mention & Keywords',
       [RoomNotificationMode.Mute]: 'Mute',
     }),
-    []
+    [],
   );
 
 type NotificationModeSwitcherProps = {
@@ -37,7 +37,7 @@ type NotificationModeSwitcherProps = {
   children: (
     handleOpen: MouseEventHandler<HTMLButtonElement>,
     opened: boolean,
-    changing: boolean
+    changing: boolean,
   ) => ReactNode;
 };
 export function RoomNotificationModeSwitcher({