feat: polish Shopee update checks

app/db.py

@@ -678,6 +678,35 @@ def set_generated(task_id, new_title, new_cover_path, path=None, conn=None) -> N
                 (new_title, new_cover_path, now, now, int(task_id)),
             )
 
+def update_generated_title(task_id, new_title, path=None, conn=None) -> None:
+    """Update a generated title manually without touching Shopee or local cover files."""
+
+    title = str(new_title or "").strip()
+    if not title:
+        raise DbError("新标题不能为空")
+    with _connection(conn, path) as database:
+        task = get_task(task_id, conn=database)
+        if task is None:
+            raise DbError(f"任务不存在或批次已删除: {task_id}")
+        if int(task.committed or 0) == 1 or task.stage == "applied":
+            raise DbError("已提交线上商品不能在本地直接修改新标题")
+        if task.stage != "generated":
+            raise DbError("只有已生成且未提交线上的任务可以修改新标题")
+        if task.status == "running":
+            raise DbError("任务正在运行，不能修改新标题")
+        now = _now()
+        with database:
+            database.execute(
+                """
+                UPDATE tasks
+                SET new_title = ?,
+                    status = 'pending',
+                    last_error = NULL,
+                    updated_at = ?
+                WHERE id = ?
+                """,
+                (title, now, int(task_id)),
+            )
 
 def set_applied(task_id, committed, error=None, path=None, conn=None) -> None:
     now = _now()