implement event persistence and improve Mongoose TypeScript patterns

- Add event persistence: confirmed events are now saved to MongoDB
- Refactor Mongoose models to use virtuals for id field with IdVirtual interface
- Update repositories to use toJSON() with consistent type casting
- Add more test responses for chat (doctor, birthday, gym, etc.)
- Show event description in ProposedEventCard
- Change mongo-express port to 8083
- Update CLAUDE.md with Mongoose model pattern documentation

CLAUDE.md

@@ -124,6 +124,7 @@ src/
 │   ├── index.ts              # Re-exports from ./mongo
 │   └── mongo/                # MongoDB implementation
 │       ├── models/           # Mongoose schemas
+│       │   ├── types.ts      # Shared types (IdVirtual interface)
 │       │   ├── UserModel.ts
 │       │   ├── EventModel.ts
 │       │   └── ChatModel.ts
@@ -193,6 +194,35 @@ The repository pattern allows swapping databases:
 - **Implementations** (`repositories/mongo/`) are DB-specific
 - To add MySQL: create `repositories/mysql/` with TypeORM entities
 
+### Mongoose Model Pattern
+
+All Mongoose models use a consistent pattern for TypeScript-safe `id` virtuals:
+
+```typescript
+import { IdVirtual } from './types';
+
+const Schema = new Schema<Doc, Model<Doc, {}, {}, IdVirtual>, {}, {}, IdVirtual>(
+  { /* fields */ },
+  {
+    virtuals: {
+      id: {
+        get() { return this._id.toString(); }
+      }
+    },
+    toJSON: {
+      virtuals: true,
+      transform: (_, ret) => {
+        delete ret._id;
+        delete ret.__v;
+        return ret;
+      }
+    }
+  }
+);
+```
+
+Repositories use `doc.toJSON() as unknown as Type` casting (required because Mongoose's TypeScript types don't reflect virtual fields in toJSON output).
+
 ## MVP Feature Scope
 
 ### Must-Have
@@ -218,7 +248,7 @@ docker compose up -d                  # Start MongoDB + Mongo Express
 docker compose down                   # Stop services
 ```
 - MongoDB: `localhost:27017` (root/mongoose)
-- Mongo Express UI: `localhost:8081` (admin/admin)
+- Mongo Express UI: `localhost:8083` (admin/admin)
 
 ### Environment Variables
 Server requires `.env` file in `apps/server/`:
@@ -239,16 +269,16 @@ MONGODB_URI=mongodb://root:mongoose@localhost:27017/calchat?authSource=admin
   - `utils/jwt`: signToken() (verifyToken() pending)
   - `dotenv` integration for environment variables
   - `ChatController`: sendMessage(), confirmEvent(), rejectEvent()
-  - `ChatService`: processMessage() with test responses, confirmEvent(), rejectEvent()
+  - `ChatService`: processMessage() with test responses, confirmEvent() saves events to DB, rejectEvent()
 - **Stubbed (TODO):**
   - `AuthMiddleware.authenticate()`: Currently uses fake user for testing
   - `AuthController`: refresh(), logout()
   - `AuthService`: refreshToken()
   - `ChatController`: getConversations(), getConversation()
   - `MongoChatRepository`: Database persistence for chat
-  - All Event functionality
+  - `MongoEventRepository`: Only create() implemented, rest stubbed
 - **Not started:**
-  - `EventController`, `EventService`, `MongoEventRepository`
+  - `EventController`, `EventService`
   - `ClaudeAdapter` (AI integration - currently using test responses)
 
 **Shared:** Types, DTOs, constants (Day, Month), and date utilities defined and exported.
@@ -258,8 +288,8 @@ MONGODB_URI=mongodb://root:mongoose@localhost:27017/calchat?authSource=admin
 - Calendar screen has month navigation and grid display (partially functional)
 - Chat screen functional with FlashList, message sending, and event confirm/reject
 - `ApiClient`: get(), post() implemented
-- `ChatService`: sendMessage(), confirmEvent(), rejectEvent() implemented
-- `ProposedEventCard`: Displays proposed events with confirm/reject buttons, theming support
+- `ChatService`: sendMessage(), confirmEvent(convId, msgId, event), rejectEvent() - confirmEvent sends CreateEventDTO in body
+- `ProposedEventCard`: Displays proposed events (title, date, description, recurring indicator) with confirm/reject buttons
 - `Themes.tsx`: Centralized color definitions including button colors
 - Auth screens (Login, Register), Event Detail, and Note screens exist as skeletons
 - Zustand stores (AuthStore, EventsStore) defined with `throw new Error('Not implemented')`