feat: Group chat and push notifications

- Add group chat tables (chat_groups, chat_group_members, group_messages)
- Add push subscriptions table for web push notifications
- Add group service, controller, routes
- Add push service, controller, routes
- Integrate push notifications with todos, messages, group messages

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app.js

@@ -26,6 +26,8 @@ import noteRoutes from './routes/note.routes.js';
 import auditRoutes from './routes/audit.routes.js';
 import eventRoutes from './routes/event.routes.js';
 import messageRoutes from './routes/message.routes.js';
+import groupRoutes from './routes/group.routes.js';
+import pushRoutes from './routes/push.routes.js';
 import userRoutes from './routes/user.routes.js';
 import serviceRoutes from './routes/service.routes.js';
 import emailSignatureRoutes from './routes/email-signature.routes.js';
@@ -123,6 +125,8 @@ app.use('/api/notes', noteRoutes);
 app.use('/api/audit-logs', auditRoutes);
 app.use('/api/events', eventRoutes);
 app.use('/api/messages', messageRoutes);
+app.use('/api/groups', groupRoutes);
+app.use('/api/push', pushRoutes);
 app.use('/api/users', userRoutes);
 app.use('/api/services', serviceRoutes);
 app.use('/api/email-signature', emailSignatureRoutes);