Add Python agent, WebSocket relay, real viewer, enrollment tokens

- WebSocket relay service (FastAPI) bridges agents and viewers
- Python agent with screen capture (mss), input control (pynput),
  script execution, and auto-reconnect
- Windows service wrapper, PyInstaller spec, NSIS installer for
  silent mass deployment (RemoteLink-Setup.exe /S /SERVER= /ENROLL=)
- Enrollment token system: admin generates tokens, agents self-register
- Real WebSocket viewer replaces simulated canvas
- Linux agent binary served from /downloads/remotelink-agent-linux
- DB migration 0002: viewer_token on sessions, enrollment_tokens table
- Sign-up pages cleaned up (invite-only redirect)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -24,6 +24,7 @@ services:
       dockerfile: Dockerfile
       args:
         NEXT_PUBLIC_APP_URL: ${NEXT_PUBLIC_APP_URL:-http://localhost:3000}
+        NEXT_PUBLIC_RELAY_URL: ${NEXT_PUBLIC_RELAY_URL:-localhost:8765}
     image: remotelink:latest
     container_name: remotelink-app
     restart: unless-stopped
@@ -33,11 +34,27 @@ services:
       DATABASE_URL: postgresql://${POSTGRES_USER:-remotelink}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-remotelink}
       AUTH_SECRET: ${AUTH_SECRET}
       NEXT_PUBLIC_APP_URL: ${NEXT_PUBLIC_APP_URL:-http://localhost:3000}
+      NEXT_PUBLIC_RELAY_URL: ${NEXT_PUBLIC_RELAY_URL:-localhost:8765}
     env_file:
       - .env
     depends_on:
       postgres:
         condition: service_healthy
 
+  relay:
+    build:
+      context: ./relay
+      dockerfile: Dockerfile
+    image: remotelink-relay:latest
+    container_name: remotelink-relay
+    restart: unless-stopped
+    ports:
+      - "8765:8765"
+    environment:
+      DATABASE_URL: postgresql://${POSTGRES_USER:-remotelink}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-remotelink}
+    depends_on:
+      postgres:
+        condition: service_healthy
+
 volumes:
   postgres_data: