fix: Dropdown choices initialization and update logic

app.py

@@ -196,7 +196,16 @@ def delete_account(email_to_delete: str):
 
 
 def get_account_emails():
-    """获取所有账号邮箱列表"""
+    """获取所有账号邮箱列表 (用于更新 Dropdown)"""
+    accounts = account_manager.get_all_accounts()
+    if not accounts:
+        return gr.update(choices=["暂无账号"], value=None)
+    emails = [acc.email for acc in accounts]
+    return gr.update(choices=emails, value=None)
+
+
+def _get_account_emails_list():
+    """获取账号邮箱列表 (用于初始化)"""
     accounts = account_manager.get_all_accounts()
     if not accounts:
         return ["暂无账号"]
@@ -333,7 +342,7 @@ with gr.Blocks(
             with gr.Row():
                 delete_email_dropdown = gr.Dropdown(
                     label="选择要删除的账号",
-                    choices=get_account_emails(),
+                    choices=_get_account_emails_list(),
                     interactive=True
                 )
                 delete_btn = gr.Button("🗑️ 删除账号", variant="stop")