fix: clarify AI generation failure retry states

app/ai.py

@@ -222,6 +222,28 @@ def _notify_retry(callback, step, attempt, attempts, exc, model):
     except Exception:
         pass
 
+
+def _task_attempt_count(task, field):
+    try:
+        return int(getattr(task, field, 0) or 0)
+    except (TypeError, ValueError):
+        return 0
+
+
+def is_generatable_task(task):
+    """判断任务是否能由② AI生成执行或重试。"""
+
+    stage = str(getattr(task, "stage", "") or "")
+    status = str(getattr(task, "status", "") or "")
+    if status in {"running", "skipped"}:
+        return False
+    if stage == "collected":
+        return True
+    if stage == "generated" and status == "failed":
+        return _task_attempt_count(task, "apply_attempts") == 0
+    return False
+
+
 def generate_batch(tasks, prompts, ai_cfg=None, on_progress=None, should_stop=None):
     """Generate titles first, then covers, and persist each successful task."""
 
@@ -256,7 +278,7 @@ def generate_batch(tasks, prompts, ai_cfg=None, on_progress=None, should_stop=No
     should_stop = should_stop or (lambda: False)
     eligible = [
         task for task in list(tasks)
-        if getattr(task, "stage", None) == "collected"
+        if is_generatable_task(task)
     ]
     summary = {
         "ok": True,