Refactor response handling and health check endpoints

- Enhance response model with additional fields and validation
- Update health and server router implementations
- Improve frontend type definitions and API integration
- Clean up documentation

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

frontend/src/api/health.ts

@@ -1,6 +1,6 @@
 import { get } from "./client";
 import { ENDPOINTS } from "./endpoints";
-import type { HealthResponse } from "../types/server";
+import type { HealthResponse } from "../types/response";
 
 export async function fetchHealth(): Promise<HealthResponse> {
   return get<HealthResponse>(ENDPOINTS.health);

frontend/src/types/response.ts

@@ -36,3 +36,23 @@ export interface ErrorResponse {
   /** Unique ID for correlating this error with request logs on both frontend and backend. */
   correlation_id?: string;
 }
+
+/**
+ * Standardized health check response.
+ * Mirrors `backend/app/models/response.py:HealthResponse`.
+ */
+export interface HealthResponse {
+  /** Application health status: 'ok' when healthy, 'unavailable' otherwise. */
+  status: "ok" | "unavailable";
+  /** fail2ban daemon status: 'online' when reachable, 'offline' otherwise. */
+  fail2ban: "online" | "offline";
+}
+
+/**
+ * Standardized flush-logs command response.
+ * Mirrors `backend/app/models/response.py:FlushLogsResponse`.
+ */
+export interface FlushLogsResponse {
+  /** Human-readable result message from fail2ban. */
+  message: string;
+}

frontend/src/types/server.ts

@@ -4,6 +4,8 @@
  * `backend/app/models/server.py`
  */
 
+import type { HealthResponse as HealthResponseBase } from "./response";
+
 /** Cached fail2ban server health snapshot. */
 export interface ServerStatus {
   /** Whether fail2ban is reachable via its socket. */
@@ -23,8 +25,8 @@ export interface ServerStatusResponse {
   status: ServerStatus;
 }
 
-/** Response shape for ``GET /api/health``. */
-export interface HealthResponse {
-  status: "ok";
-  fail2ban: "online" | "offline";
-}
+/**
+ * Response shape for ``GET /api/health``.
+ * Re-exports the canonical type from `types/response.ts`.
+ */
+export type HealthResponse = HealthResponseBase;