Refactor app helpers and use AppStateDep in config router

Move service-dependent helper wrappers from app.utils to app.helpers and update config router activation/rollback to use explicit AppState dependency.

backend/app/services/config_service.py

@@ -29,6 +29,8 @@ if TYPE_CHECKING:
 
 from app import __version__
 from app.exceptions import ConfigOperationError, ConfigValidationError, JailNotFoundError
+from app.helpers.log_helpers import preview_log as util_preview_log
+from app.helpers.log_helpers import test_regex as util_test_regex
 from app.models.config import (
     AddLogPathRequest,
     BantimeEscalation,
@@ -48,8 +50,6 @@ from app.models.config import (
     ServiceStatusResponse,
 )
 from app.utils.fail2ban_client import Fail2BanClient
-from app.utils.log_utils import preview_log as util_preview_log
-from app.utils.log_utils import test_regex as util_test_regex
 from app.utils.setup_utils import (
     get_map_color_thresholds as util_get_map_color_thresholds,
 )