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

apps/server/docker/mongo/docker-compose.yml

@@ -0,0 +1,33 @@
+services:
+  mongo:
+    image: mongo:8
+    restart: always
+    ports:
+      - "27017:27017"
+    environment:
+      MONGO_INITDB_ROOT_USERNAME: root
+      MONGO_INITDB_ROOT_PASSWORD: mongoose
+    volumes:
+      - mongo-data:/data/db
+    healthcheck:
+      test: mongosh --eval "db.adminCommand('ping')"
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  mongo-express:
+    image: mongo-express:latest
+    restart: always
+    ports:
+      - "8083:8081"
+    environment:
+      ME_CONFIG_MONGODB_URL: mongodb://root:mongoose@mongo:27017/
+      ME_CONFIG_BASICAUTH_ENABLED: true
+      ME_CONFIG_BASICAUTH_USERNAME: admin
+      ME_CONFIG_BASICAUTH_PASSWORD: admin
+    depends_on:
+      mongo:
+        condition: service_healthy
+
+volumes:
+  mongo-data: