fix: add INTERNAL_SECRET to api environment variables

Added INTERNAL_SECRET environment variable to the api service in docker-compose.yml.
This fixes the pydantic validation error that was causing the API to fail to start.

The INTERNAL_SECRET is required for internal service-to-service communication
(nc-watcher → API) and was missing from the container environment.

docker-compose.yml

@@ -49,6 +49,7 @@ services:
       NEXTCLOUD_PASS: ${NEXTCLOUD_PASS:-default_password}
       REDIS_URL: redis://redis:6379/0
       SECRET_KEY: ${SECRET_KEY:-replace_me_with_32_byte_hex_default}
+      INTERNAL_SECRET: ${INTERNAL_SECRET:-replace_me_with_32_byte_hex_default}
       DOMAIN: ${DOMAIN:-localhost}
     networks:
       - rh_net