Add filter discovery endpoints with active/inactive status (Task 2.1)

- Add list_filters() and get_filter() to config_file_service.py:
  scans filter.d/, parses [Definition] + [Init] sections, merges .local
  overrides, and cross-references running jails to set active/used_by_jails
- Add FilterConfig.active, used_by_jails, source_file, has_local_override
  fields to the Pydantic model; add FilterListResponse and FilterNotFoundError
- Add GET /api/config/filters and GET /api/config/filters/{name} to config.py
- Remove the shadowed GET /api/config/filters list route from file_config.py;
  rename GET /api/config/filters/{name} raw variant to /filters/{name}/raw
- Update frontend: fetchFilterFiles() adapts FilterListResponse -> ConfFilesResponse;
  add fetchFilters() and fetchFilter() to api/config.ts; remove unused
  fetchFilterFiles/fetchActionFiles calls from useConfigActiveStatus
- Fix ConfigPageLogPath test mock to include fetchInactiveJails and related
  exports introduced by Stage 1
- Backend: 169 tests pass, mypy --strict clean, ruff clean
- Frontend: 63 tests pass, tsc --noEmit clean, eslint clean

frontend/src/api/config.ts

@@ -15,6 +15,7 @@ import type {
   ConfFileUpdateRequest,
   FilterConfig,
   FilterConfigUpdate,
+  FilterListResponse,
   GlobalConfig,
   GlobalConfigUpdate,
   InactiveJailListResponse,
@@ -200,15 +201,27 @@ export async function setJailConfigFileEnabled(
 }
 
 // ---------------------------------------------------------------------------
-// Filter files (Task 4d)
+// Filter files (Task 4d) — raw file management
 // ---------------------------------------------------------------------------
 
+/**
+ * Return a lightweight name/filename list of all filter files.
+ *
+ * Internally calls the enriched ``GET /config/filters`` endpoint (which also
+ * returns active-status data) and maps the result down to the simpler
+ * ``ConfFilesResponse`` shape expected by the raw-file editor and export tab.
+ */
 export async function fetchFilterFiles(): Promise<ConfFilesResponse> {
-  return get<ConfFilesResponse>(ENDPOINTS.configFilters);
+  const result = await fetchFilters();
+  return {
+    files: result.filters.map((f) => ({ name: f.name, filename: f.filename })),
+    total: result.total,
+  };
 }
 
+/** Fetch the raw content of a filter definition file for the raw editor. */
 export async function fetchFilterFile(name: string): Promise<ConfFileContent> {
-  return get<ConfFileContent>(ENDPOINTS.configFilter(name));
+  return get<ConfFileContent>(ENDPOINTS.configFilterRaw(name));
 }
 
 export async function updateFilterFile(
@@ -264,6 +277,32 @@ export async function updateParsedFilter(
   await put<undefined>(ENDPOINTS.configFilterParsed(name), update);
 }
 
+// ---------------------------------------------------------------------------
+// Filter discovery with active/inactive status (Task 2.1)
+// ---------------------------------------------------------------------------
+
+/**
+ * Fetch all filters from filter.d/ with active/inactive status.
+ *
+ * Active filters (those referenced by running jails) are returned first,
+ * followed by inactive ones.  Both groups are sorted alphabetically.
+ *
+ * @returns FilterListResponse with all discovered filters and status.
+ */
+export async function fetchFilters(): Promise<FilterListResponse> {
+  return get<FilterListResponse>(ENDPOINTS.configFilters);
+}
+
+/**
+ * Fetch full parsed detail for a single filter with active/inactive status.
+ *
+ * @param name - Filter base name (e.g. "sshd" or "sshd.conf").
+ * @returns FilterConfig with active, used_by_jails, source_file populated.
+ */
+export async function fetchFilter(name: string): Promise<FilterConfig> {
+  return get<FilterConfig>(ENDPOINTS.configFilter(name));
+}
+
 // ---------------------------------------------------------------------------
 // Parsed action config (Task 3.2)
 // ---------------------------------------------------------------------------