feat：计算视频帧传来的差值

frontend/src/lib/api.ts

@@ -1,4 +1,4 @@
-import type { DashboardSnapshot } from '@/types'
+import type { DashboardSnapshot, VideoStatus } from '@/types'
 
 const envBaseUrl = import.meta.env.VITE_API_BASE_URL as string | undefined
 
@@ -16,6 +16,10 @@ export function fetchDashboardSnapshot() {
   return fetchJson<DashboardSnapshot>('/api/dashboard/')
 }
 
+export function fetchVideoStatus() {
+  return fetchJson<VideoStatus>('/api/video/status/')
+}
+
 export function buildVideoFrameUrl(frameKey: number) {
   return `${API_BASE}/api/video/frame/?frame=${frameKey}&t=${Date.now()}`
 }