CUB-119: add GET /api/health endpoint to Chi router

go-backend/internal/router/router.go

@@ -65,6 +65,21 @@ func New(deps *Dependencies) *chi.Mux {
 
 	// ── API v1 routes ──────────────────────────────────────────────────────
 	r.Route("/api", func(api chi.Router) {
+		// Health check (under /api)
+		api.Get("/health", func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/json")
+			status := "ok"
+			if deps.Pool != nil {
+				ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+				defer cancel()
+				if err := deps.Pool.Ping(ctx); err != nil {
+					w.WriteHeader(http.StatusServiceUnavailable)
+					status = "db_unhealthy"
+				}
+			}
+			w.Write([]byte(`{"status":"` + status + `"}`))
+		})
+
 		// Agents CRUD
 		api.Route("/agents", func(agents chi.Router) {
 			agents.Get("/", deps.Handler.ListAgents)            // GET /api/agents