fix: clarify AI generation failure retry states

app/gui/tabs/generate.py

@@ -470,10 +470,10 @@ class GenerateTab(QWidget):
         generate_cover = bool(self.generate_cover_checkbox.isChecked())
         tasks = [
             task for task in self.model.tasks
-            if getattr(task, "stage", None) == "collected"
+            if ai.is_generatable_task(task)
         ]
         if not tasks:
-            self._set_status("当前筛选结果没有可生成任务")
+            self._set_status("当前筛选结果没有待生成或生成失败可重试任务；请先在①导入采集完成旧数据采集")
             return
         prompt_values = {
             "title": self.title_prompt_edit.toPlainText(),
@@ -896,7 +896,7 @@ class GenerateTab(QWidget):
         if selected_status in (None, "all"):
             return True
         if selected_status == "to_generate":
-            return task.stage == "collected" and task.status in {"success", "pending"}
+            return ai.is_generatable_task(task) and task.status != "failed"
         if selected_status == "generated":
             return task.stage == "generated"
         if selected_status == "applied":