feat: Windows taskbar notification badge counter

Adds a Tauri command (set_badge_count) that draws a red circle badge
with a highlight count onto the Windows taskbar button overlay icon,
matching Discord's behavior. Badge shows @mention/highlight count only
(not total messages), clears to zero when all highlights are read.

Frontend: useTauriNotificationBadge hook reads roomToUnreadAtom and
calls set_badge_count via window.__TAURI_INTERNALS__.invoke whenever
the unread map changes. No-ops silently in the browser (non-Tauri).
Mounted as TauriEffects inside JotaiProvider in App.tsx.

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

src/app/features/settings/general/General.tsx

@@ -933,6 +933,17 @@ function Editor() {
     setComposerToolbarButtons({ ...composerToolbarButtons, [key]: !composerToolbarButtons[key] });
   };
 
+  const TOOLBAR_CHIPS: Array<{ key: keyof ComposerToolbarSettings; label: string }> = [
+    { key: 'showFormat', label: 'Format' },
+    { key: 'showEmoji', label: 'Emoji' },
+    { key: 'showSticker', label: 'Sticker' },
+    { key: 'showGif', label: 'GIF' },
+    { key: 'showLocation', label: 'Location' },
+    { key: 'showPoll', label: 'Poll' },
+    { key: 'showVoice', label: 'Voice' },
+    { key: 'showSchedule', label: 'Schedule' },
+  ];
+
   return (
     <Box direction="Column" gap="100">
       <Text size="L400">Editor</Text>
@@ -958,89 +969,32 @@ function Editor() {
           after={<Switch variant="Primary" value={editorToolbar} onChange={setEditorToolbar} />}
         />
       </SequenceCard>
-      <Text size="L400" style={{ marginTop: '8px' }}>Composer Toolbar Buttons</Text>
-      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column" gap="300">
         <SettingTile
-          title="Format Toggle"
-          description="Button to show/hide the text formatting toolbar."
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showFormat ?? true}
-              onChange={() => toggleToolbarButton('showFormat')}
-            />
-          }
-        />
-        <SettingTile
-          title="Emoji"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showEmoji ?? true}
-              onChange={() => toggleToolbarButton('showEmoji')}
-            />
-          }
-        />
-        <SettingTile
-          title="Sticker"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showSticker ?? true}
-              onChange={() => toggleToolbarButton('showSticker')}
-            />
-          }
-        />
-        <SettingTile
-          title="GIF"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showGif ?? true}
-              onChange={() => toggleToolbarButton('showGif')}
-            />
-          }
-        />
-        <SettingTile
-          title="Location"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showLocation ?? true}
-              onChange={() => toggleToolbarButton('showLocation')}
-            />
-          }
-        />
-        <SettingTile
-          title="Poll"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showPoll ?? true}
-              onChange={() => toggleToolbarButton('showPoll')}
-            />
-          }
-        />
-        <SettingTile
-          title="Voice Message"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showVoice ?? true}
-              onChange={() => toggleToolbarButton('showVoice')}
-            />
-          }
-        />
-        <SettingTile
-          title="Schedule Message"
-          after={
-            <Switch
-              variant="Primary"
-              value={composerToolbarButtons?.showSchedule ?? true}
-              onChange={() => toggleToolbarButton('showSchedule')}
-            />
-          }
+          title="Composer Toolbar"
+          description="Tap a button to show or hide it in the message composer."
         />
+        <Box
+          wrap="Wrap"
+          gap="200"
+          style={{ padding: `0 ${config.space.S400} ${config.space.S300}` }}
+        >
+          {TOOLBAR_CHIPS.map(({ key, label }) => {
+            const active = composerToolbarButtons?.[key] ?? true;
+            return (
+              <Chip
+                key={key}
+                variant={active ? 'Primary' : 'Secondary'}
+                outlined={active}
+                radii="Pill"
+                onClick={() => toggleToolbarButton(key)}
+                aria-pressed={active}
+              >
+                <Text size="T300">{label}</Text>
+              </Chip>
+            );
+          })}
+        </Box>
       </SequenceCard>
     </Box>
   );

src/app/hooks/useTauriNotificationBadge.ts

@@ -0,0 +1,25 @@
+import { useEffect } from 'react';
+import { useAtomValue } from 'jotai';
+import { roomToUnreadAtom } from '../state/room/roomToUnread';
+
+// Tauri v2 injects __TAURI_INTERNALS__ into the webview at runtime.
+// We use it directly so cinny doesn't need @tauri-apps/api as a dependency.
+type TauriInternals = { invoke: (cmd: string, args?: Record<string, unknown>) => Promise<unknown> };
+const tauriInvoke = (): TauriInternals['invoke'] | undefined =>
+  (window as unknown as { __TAURI_INTERNALS__?: TauriInternals }).__TAURI_INTERNALS__?.invoke;
+
+export function useTauriNotificationBadge() {
+  const roomToUnread = useAtomValue(roomToUnreadAtom);
+
+  useEffect(() => {
+    const invoke = tauriInvoke();
+    if (!invoke) return;
+
+    let totalHighlights = 0;
+    roomToUnread.forEach((unread) => {
+      totalHighlights += unread.highlight;
+    });
+
+    invoke('set_badge_count', { count: totalHighlights }).catch(() => {});
+  }, [roomToUnread]);
+}

src/app/pages/App.tsx

@@ -15,6 +15,7 @@ import { ScreenSizeProvider, useScreenSize } from '../hooks/useScreenSize';
 import { useCompositionEndTracking } from '../hooks/useComposingCheck';
 import { settingsAtom } from '../state/settings';
 import { LotusToastContainer } from '../features/toast/LotusToastContainer';
+import { useTauriNotificationBadge } from '../hooks/useTauriNotificationBadge';
 
 const FONT_MAP: Record<string, string> = {
   system: "system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif",
@@ -52,6 +53,11 @@ function AppearanceEffects() {
   return null;
 }
 
+function TauriEffects() {
+  useTauriNotificationBadge();
+  return null;
+}
+
 function NightLightOverlay() {
   const settings = useAtomValue(settingsAtom);
   if (!settings.nightLightEnabled) return null;
@@ -131,6 +137,7 @@ function App() {
                       <QueryClientProvider client={queryClient}>
                         <JotaiProvider>
                           <AppearanceEffects />
+                          <TauriEffects />
                           <RouterProvider router={createRouter(clientConfig, screenSize)} />
                           <NightLightOverlay />
                           <LotusToastContainer />