refactor(admin): remove legacy admin fallback page and routing

routes/pages.py

@@ -6,7 +6,7 @@ import json
 import os
 from typing import Optional
 
-from flask import Blueprint, current_app, redirect, render_template, request, session, url_for
+from flask import Blueprint, current_app, redirect, render_template, session, url_for
 from flask_login import current_user, login_required
 
 from routes.decorators import admin_required
@@ -72,13 +72,6 @@ def _get_asset_build_id(static_root: str, rel_paths: list[str]) -> Optional[str]
     return str(int(max(mtimes)))
 
 
-def _is_legacy_admin_user_agent(user_agent: str) -> bool:
-    if not user_agent:
-        return False
-    ua = user_agent.lower()
-    return "msie" in ua or "trident/" in ua
-
-
 @pages_bp.route("/")
 def index():
     """主页 - 重定向到登录或应用"""
@@ -125,8 +118,6 @@ def admin_login_page():
 @admin_required
 def admin_page():
     """后台管理页面"""
-    if request.args.get("legacy") == "1" or _is_legacy_admin_user_agent(request.headers.get("User-Agent", "")):
-        return render_template("admin_legacy.html")
     logger = get_logger()
     manifest_path = os.path.join(current_app.root_path, "static", "admin", ".vite", "manifest.json")
     try:
@@ -138,8 +129,8 @@ def admin_page():
         css_files = entry.get("css") or []
 
         if not js_file:
-            logger.warning(f"[admin_spa] manifest缺少入口文件: {manifest_path}")
-            return render_template("admin_legacy.html")
+            logger.error(f"[admin_spa] manifest缺少入口文件: {manifest_path}")
+            return "后台前端资源缺失，请重新构建管理端", 503
 
         admin_spa_js_file = f"admin/{js_file}"
         admin_spa_css_files = [f"admin/{p}" for p in css_files]
@@ -155,8 +146,8 @@ def admin_page():
             admin_spa_build_id=admin_spa_build_id,
         )
     except FileNotFoundError:
-        logger.warning(f"[admin_spa] 未找到manifest: {manifest_path}，回退旧版后台模板")
-        return render_template("admin_legacy.html")
+        logger.error(f"[admin_spa] 未找到manifest: {manifest_path}")
+        return "后台前端资源未构建，请联系管理员", 503
     except Exception as e:
         logger.error(f"[admin_spa] 加载manifest失败: {e}")
-        return render_template("admin_legacy.html")
+        return "后台页面加载失败，请稍后重试", 500