feat: DM infrastructure overhaul + volume sliders + LiveKit dynamic URL

- Add DM edit/delete endpoints (REST + WebSocket)
- Add DM typing indicators with real-time broadcast
- Fix volume sliders to control LiveKit mic/speaker
- Fix Send Message button on user profile popout
- Add New DM modal with user search
- Fix message pagination (SQL cursor instead of in-memory)
- Guard optional attachments on DM messages
- Dynamic LiveKit URL from request Host header
- DM sidebar auto-sorts by most recent message

packages/server/src/db/index.ts

@@ -117,6 +117,15 @@ function createTables(db: Database.Database): void {
       UNIQUE(message_id, user_id, emoji)
     );
 
+    CREATE TABLE IF NOT EXISTS dm_reactions (
+      id TEXT PRIMARY KEY,
+      dm_message_id TEXT NOT NULL,
+      user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+      emoji TEXT NOT NULL,
+      created_at INTEGER NOT NULL,
+      UNIQUE(dm_message_id, user_id, emoji)
+    );
+
     CREATE TABLE IF NOT EXISTS roles (
       id TEXT PRIMARY KEY,
       server_id TEXT NOT NULL REFERENCES servers(id) ON DELETE CASCADE,