feat: add connections dashboard with background health checks

- Add /connections page showing all integrations with online/offline status
- Add background health checker that polls Evotor API every 10 minutes
- Add is_online and last_checked_at fields to evotor_connections table
- Replace Evotor navbar link with unified Connections link
- Redirect connect/disconnect flows to /connections
- Add Alembic migration for new columns

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

docker-compose.yml

@@ -16,12 +16,12 @@ services:
       - ./alembic.ini:/app/alembic.ini
       - ./docker-entrypoint.sh:/app/docker-entrypoint.sh
 
-  sync:
-    build:
-      context: .
-      dockerfile: Dockerfile
-    volumes:
-      - ./evo:/var/www/evo
-      - ./vk:/var/www/vk
-      - ./run:/var/www/run
-      - ./logs:/var/www/logs
+  # sync:
+  #   build:
+  #     context: .
+  #     dockerfile: Dockerfile
+  #   volumes:
+  #     - ./evo:/var/www/evo
+  #     - ./vk:/var/www/vk
+  #     - ./run:/var/www/run
+  #     - ./logs:/var/www/logs