fix: replace broad except Exception with specific exception types

- jail_service: catch ValueError (fail2ban protocol error) instead of Exception
- health.py: catch AttributeError (not OSError/TypeError) for defensive checks
- ban_service: re-raise programming errors in geo lookup handlers
- server_service: catch Fail2BanConnectionError, Fail2BanProtocolError, ValueError
- config_writer: catch OSError instead of Exception

Programming errors now bubble to global handler instead of being silently caught.

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

backend/app/services/jail_service.py

@@ -159,12 +159,13 @@ async def _check_backend_cmd_supported(
         if state.backend_cmd_supported is not None:
             return state.backend_cmd_supported
 
-        # Probe: send the command and catch any exception.
+        # Probe: send the command and catch only fail2ban protocol errors.
+        # Programming errors (TypeError, AttributeError) bubble up to global handler.
         try:
             ok(await client.send(["get", jail_name, "backend"]))
             state.backend_cmd_supported = True
             log.debug("backend_cmd_supported_detected")
-        except Exception:
+        except ValueError:
             state.backend_cmd_supported = False
             log.debug("backend_cmd_unsupported_detected")