Harden async task flows and enhance analysis tooling

server/db.ts

@@ -1631,7 +1631,11 @@ export async function claimNextBackgroundTask(workerId: string) {
 
   const now = new Date();
   const [nextTask] = await db.select().from(backgroundTasks)
-    .where(and(eq(backgroundTasks.status, "queued"), lte(backgroundTasks.runAfter, now)))
+    .where(and(
+      eq(backgroundTasks.status, "queued"),
+      lte(backgroundTasks.runAfter, now),
+      sql`${backgroundTasks.attempts} < ${backgroundTasks.maxAttempts}`,
+    ))
     .orderBy(asc(backgroundTasks.runAfter), asc(backgroundTasks.createdAt))
     .limit(1);
 
@@ -1733,6 +1737,24 @@ export async function retryBackgroundTask(userId: number, taskId: string) {
   return getBackgroundTaskById(taskId);
 }
 
+export async function failExhaustedBackgroundTasks(now: Date = new Date()) {
+  const db = await getDb();
+  if (!db) return;
+  await db.update(backgroundTasks).set({
+    status: "failed",
+    progress: 100,
+    message: "任务达到最大重试次数，已停止自动重试",
+    error: sql`coalesce(${backgroundTasks.error}, '任务达到最大重试次数')`,
+    workerId: null,
+    lockedAt: null,
+    completedAt: now,
+  }).where(and(
+    eq(backgroundTasks.status, "queued"),
+    lte(backgroundTasks.runAfter, now),
+    sql`${backgroundTasks.attempts} >= ${backgroundTasks.maxAttempts}`,
+  ));
+}
+
 export async function requeueStaleBackgroundTasks(staleBefore: Date) {
   const db = await getDb();
   if (!db) return;