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/features/room/RoomView.tsx

@@ -92,14 +92,14 @@ export function RoomView({ eventId }: { eventId?: string }) {
           ReactEditor.focus(editor);
         }
       },
-      [editor]
-    )
+      [editor],
+    ),
   );
 
   const chatBgStyle = useMemo(
     () =>
       getChatBg(lotusTerminal && chatBackground === 'none' ? 'tactical' : chatBackground, isDark),
-    [chatBackground, lotusTerminal, isDark]
+    [chatBackground, lotusTerminal, isDark],
   );
 
   return (