Refactor backend services and jail configuration

- Refactor action_config_service, filter_config_service, jail_config_service, and jail_service
- Add jail_socket utility module for socket communication
- Update test_jail_service with new test cases
- Update architecture and task documentation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Docs/Architekture.md

@@ -252,6 +252,7 @@ Pure helper modules with no framework dependencies.
 | Module | Purpose |
 |---|---|
 | `fail2ban_client.py` | Async client that communicates with fail2ban via its Unix domain socket — sends commands and parses responses using the fail2ban protocol. Modelled after [`./fail2ban-master/fail2ban/client/csocket.py`](../fail2ban-master/fail2ban/client/csocket.py) and [`./fail2ban-master/fail2ban/client/fail2banclient.py`](../fail2ban-master/fail2ban/client/fail2banclient.py). |
+| `jail_socket.py` | Low-level jail reload operations (`reload_all`) extracted to break service dependencies. Used by `jail_service`, `jail_config_service`, `action_config_service`, and `filter_config_service` to avoid circular imports between sibling services. |
 | `ip_utils.py` | Validates IPv4/IPv6 addresses and CIDR ranges using the `ipaddress` stdlib module, normalises formats |
 | `jail_utils.py` | Jail helper functions for configuration and status inference |
 | `jail_config.py` | Jail config parser and serializer for fail2ban config manipulation |
@@ -774,6 +775,7 @@ These principles govern all architectural decisions in BanGUI.
 | Principle | Application |
 |---|---|
 | **Separation of Concerns** | Frontend and backend are independent. Backend layers (router → service → repository) never mix responsibilities. |
+| **Service Independence** | Services must not import other services at the same layer (e.g., `jail_config_service` must not import `jail_service`). Shared logic belongs in the utils layer (`app/utils/`). This prevents circular dependencies, improves testability, and keeps each service focused on its domain. |
 | **Single Responsibility** | Each module, service, and component has one well-defined job. |
 | **Dependency Inversion** | Services depend on abstractions (protocols), not concrete implementations. FastAPI `Depends()` wires everything. |
 | **Async Everything** | All I/O is non-blocking. No synchronous database, HTTP, or socket calls anywhere in the backend. |