feat(server): integrate UDP video service and normalize database schema

- Implement UDPVideoService to stream MJPEG video frames from ESP32s via UDP and send control commands.
- Normalize race database schema:
  - Remove redundant driver_ids array from races table (migration 011).
  - Move per-driver outcomes (total_time_ms, best_lap_ms, position) to race_drivers table (migration 012).
  - Add device_id column to lobby_drivers to link active physical devices (migration 013).
- Update WebSocket handler to pass lobbySvc, driversSvc, and videoSvc for driver identity tracking, syncing in-memory driver metadata, and forwarding WS controls to physical cars.
- Add CORS middleware to HTTP routes.
- Regenerate Swagger documentation.

server/internal/realtime/hub.go

@@ -13,11 +13,13 @@ import (
 
 // Client is a single connected WebSocket client.
 type Client struct {
-	ID        string
-	Send      chan []byte
-	SessionID string
-	Done      chan struct{}
-	once      sync.Once
+	ID             string
+	Send           chan []byte
+	SessionID      string
+	Done           chan struct{}
+	once           sync.Once
+	DriverID       string
+	LastUDPCommand string
 }
 
 // Close signals the read/write pumps to exit and frees the send channel.