fix(server): set no-cache headers on index.html to prevent stale SPA bundles

cmd/server/main.go

@@ -446,9 +446,13 @@ func main() {
 			// If the file exists, serve it; otherwise serve index.html (SPA fallback)
 			path := staticDir + r.URL.Path
 			if _, err := os.Stat(path); os.IsNotExist(err) {
+				w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 				http.ServeFile(w, r, staticDir+"/index.html")
 				return
 			}
+			if r.URL.Path == "/" || r.URL.Path == "/index.html" {
+				w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+			}
 			fileServer.ServeHTTP(w, r)
 		})
 	}