feat: swipe gestures, pin/mute, last seen, emoji fix, push/rename fixes

- Add swipe-to-reveal in mobile chat list (right=pin, left=mute/leave)
- Pin/mute API endpoints with is_pinned DB column migration
- Show pin icon on pinned chats, mute icon on muted chats
- Pinned chats sort to top of list
- Fix push notifications sent to message sender (filter uid)
- Remove debug console.log from WS handler
- Fix chat rename not updating in sidebar without reload
- Fix emoji picker z-index and positioning on mobile (z-50, bottom-full)
- Add last seen time in chat header for private chats

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

backend/src/routes/chats.ts

@@ -16,7 +16,7 @@ export default async function chatRoutes(app: FastifyInstance) {
     const { rows } = await pool.query(`
       SELECT
         c.id, c.type, c.title, c.description, c.avatar_color, c.avatar, c.is_public, c.created_at,
-        cm.role, cm.last_read_at,
+        cm.role, cm.last_read_at, cm.is_pinned, cm.is_muted,
         (SELECT content FROM messages WHERE chat_id = c.id AND is_deleted = FALSE ORDER BY created_at DESC LIMIT 1) AS last_message,
         (SELECT created_at FROM messages WHERE chat_id = c.id AND is_deleted = FALSE ORDER BY created_at DESC LIMIT 1) AS last_message_at,
         (SELECT COUNT(*) FROM messages WHERE chat_id = c.id AND is_deleted = FALSE AND created_at > cm.last_read_at) AS unread_count,
@@ -44,7 +44,7 @@ export default async function chatRoutes(app: FastifyInstance) {
         ) END AS private_user_id
       FROM chats c
       JOIN chat_members cm ON cm.chat_id = c.id AND cm.user_id = $1
-      ORDER BY COALESCE(
+      ORDER BY cm.is_pinned DESC, COALESCE(
         (SELECT created_at FROM messages WHERE chat_id = c.id AND is_deleted = FALSE ORDER BY created_at DESC LIMIT 1),
         c.created_at
       ) DESC
@@ -65,6 +65,8 @@ export default async function chatRoutes(app: FastifyInstance) {
       memberCount: parseInt(r.member_count),
       privateUserId: r.private_user_id,
       createdAt: r.created_at,
+      isPinned: r.is_pinned,
+      isMuted: r.is_muted,
     }));
   });
 
@@ -308,6 +310,24 @@ export default async function chatRoutes(app: FastifyInstance) {
     return { ok: true };
   });
 
+  // Pin/unpin chat for current user
+  app.put('/:id/pin', async (req) => {
+    const { id: userId } = req.user as { id: string };
+    const { id } = req.params as { id: string };
+    const { pinned } = req.body as { pinned: boolean };
+    await pool.query('UPDATE chat_members SET is_pinned = $1 WHERE chat_id = $2 AND user_id = $3', [pinned, id, userId]);
+    return { ok: true };
+  });
+
+  // Mute/unmute chat for current user
+  app.put('/:id/mute', async (req) => {
+    const { id: userId } = req.user as { id: string };
+    const { id } = req.params as { id: string };
+    const { muted } = req.body as { muted: boolean };
+    await pool.query('UPDATE chat_members SET is_muted = $1 WHERE chat_id = $2 AND user_id = $3', [muted, id, userId]);
+    return { ok: true };
+  });
+
   // Leave chat
   app.delete('/:id/leave', async (req, reply) => {
     const { id: userId } = req.user as { id: string };