feat: Stage 4 — fail2ban connection and server status

frontend/src/types/server.ts

@@ -0,0 +1,24 @@
+/**
+ * TypeScript interfaces that mirror the backend's server status Pydantic models.
+ *
+ * `backend/app/models/server.py`
+ */
+
+/** Cached fail2ban server health snapshot. */
+export interface ServerStatus {
+  /** Whether fail2ban is reachable via its socket. */
+  online: boolean;
+  /** fail2ban version string, or null when offline. */
+  version: string | null;
+  /** Number of currently active jails. */
+  active_jails: number;
+  /** Aggregated current ban count across all jails. */
+  total_bans: number;
+  /** Aggregated current failure count across all jails. */
+  total_failures: number;
+}
+
+/** Response shape for ``GET /api/dashboard/status``. */
+export interface ServerStatusResponse {
+  status: ServerStatus;
+}