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/helpers/jail_helpers.py

@@ -0,0 +1,23 @@
+"""Shared jail management helpers for service-layer code."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from app.services.jail_service import reload_all
+
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+
+
+async def reload_jails(
+    socket_path: str,
+    include_jails: Sequence[str] | None = None,
+    exclude_jails: Sequence[str] | None = None,
+) -> None:
+    """Reload fail2ban jails using the shared jail service helper."""
+    await reload_all(
+        socket_path,
+        include_jails=list(include_jails) if include_jails is not None else None,
+        exclude_jails=list(exclude_jails) if exclude_jails is not None else None,
+    )