feat: async task pipeline for media and llm workflows

client/src/lib/media.ts

@@ -53,14 +53,40 @@ export type MediaSession = {
 };
 
 const MEDIA_BASE = (import.meta.env.VITE_MEDIA_BASE_URL || "/media").replace(/\/$/, "");
+const RETRYABLE_STATUS = new Set([502, 503, 504]);
+
+function sleep(ms: number) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
 
 async function request<T>(path: string, init?: RequestInit): Promise<T> {
-  const response = await fetch(`${MEDIA_BASE}${path}`, init);
-  if (!response.ok) {
-    const errorBody = await response.json().catch(() => ({}));
-    throw new Error(errorBody.error || errorBody.message || `Media service error (${response.status})`);
+  let lastError: Error | null = null;
+
+  for (let attempt = 0; attempt < 3; attempt++) {
+    try {
+      const response = await fetch(`${MEDIA_BASE}${path}`, init);
+      if (!response.ok) {
+        const errorBody = await response.json().catch(() => ({}));
+        const error = new Error(errorBody.error || errorBody.message || `Media service error (${response.status})`);
+        if (RETRYABLE_STATUS.has(response.status) && attempt < 2) {
+          lastError = error;
+          await sleep(400 * (attempt + 1));
+          continue;
+        }
+        throw error;
+      }
+      return response.json() as Promise<T>;
+    } catch (error) {
+      lastError = error instanceof Error ? error : new Error("Media request failed");
+      if (attempt < 2) {
+        await sleep(400 * (attempt + 1));
+        continue;
+      }
+      throw lastError;
+    }
   }
-  return response.json() as Promise<T>;
+
+  throw lastError || new Error("Media request failed");
 }
 
 export async function createMediaSession(payload: {