feat: Implement dynamic Gatekeeper proxy and enhance service health monitoring

- **Implemented Dynamic Gatekeeper (Anubis) Proxy:**
  - Introduced Anubis as a Gatekeeper proxy layer for services (`web`, `web-staging`, `feedback`, `health`).
  - Added `docker-gen` setup (`docker-compose_gatekeeper.template.yml`, `gatekeeper-manager`) to dynamically configure Anubis instances based on container labels (`enable_gatekeeper=true`).
  - Updated HAProxy to route traffic through the respective Gatekeeper services.

- **Enhanced Service Health Monitoring & Checks:**
  - Integrated `django-health-check` into the Django application, providing detailed health endpoints (e.g., `/health/`).
  - Replaced the custom health check view with `django-health-check` URLs.
  - Added `psutil` for system metrics in health checks.
  - Made Gatus configuration dynamic using `docker-gen` (`config.template.yaml`), allowing automatic discovery and monitoring of service instances (e.g., web workers).
  - Externalized Gatus SMTP credentials to environment variables.
  - Strengthened `docker-compose_core.yml` with a combined `db-redis-healthcheck` service reporting to Gatus.
  - Added explicit health checks for `db` and `redis` services in `docker-compose.yml`.

- **Improved Docker & Compose Configuration:**
  - Added `depends_on` conditions in `docker-compose.yml` for `web` and `celery` services to wait for the database.
  - Updated `ALLOWED_HOSTS` in `docker-compose_staging.yml` and `docker-compose_web.yml` to include internal container names for Gatekeeper communication.
  - Set `DEBUG=False` for staging services.
  - Removed `.env.production` from `.gitignore` (standardized to `.env`).
  - Streamlined `scripts/entrypoint.sh` by removing the call to the no-longer-present `/deploy.sh`.

- **Dependency Updates:**
  - Added `django-health-check>=3.18.3` and `psutil>=7.0.0` to `pyproject.toml` and `uv.lock`.
  - Updated `settings.py` to include `health_check` apps, configuration, and use `REDIS_URL` consistently.

- **Streamlined deployment script used in GHA:**
  - Updated the workflow to copy new server files and create a new `.env` file in the temporary directory before moving them into place.
  - Consolidated the stopping and removal of old containers into a single step for better clarity and efficiency.
  - Reduce container downtime by rearranging stop/start steps.

scripts/entrypoint.sh

@@ -13,8 +13,5 @@ else
  export DJANGO_SETTINGS_MODULE=$DJANGO_SETTINGS_MODULE
 fi
 
-echo "Running deploy.sh... (if you get a APP_REGISTRY_NOT_READY error, there's probably an error in settings.py)"
-/deploy.sh
-
-echo "Environment is correct and deploy.sh has been run - executing command: '$@'"
+echo "Environment is correct - executing command: '$@'"
 exec "$@" && exit 0