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/utils/config_writer.py

@@ -150,7 +150,7 @@ def _write_parser_atomic(
         with os.fdopen(fd, "w", encoding="utf-8") as f:
             f.write(content)
         os.replace(tmp_path_str, str(path))
-    except Exception:
+    except OSError:
         with contextlib.suppress(OSError):
             os.unlink(tmp_path_str)
         raise