feat: 完成 Passkey 能力与前后台加载优化

更新说明：\n1. 新增用户端与管理员端 Passkey 登录/注册/设备管理（最多3台，支持设备备注、删除设备）。\n2. 修复 Passkey 注册与登录流程中的浏览器/证书/CSRF相关问题，增强错误提示。\n3. 前台登录页改为独立入口，首屏仅加载必要资源，其他页面按需加载。\n4. 系统配置页改为静默获取金山文档状态，避免首屏阻塞，并优化状态展示为“检测中/已登录/未登录/异常”。\n5. 补充后端接口与页面渲染适配，修复多入口下样式依赖注入问题。\n6. 同步更新前后台构建产物与相关静态资源。

routes/api_screenshots.py

@@ -9,7 +9,7 @@ from typing import Iterator
 import database
 from app_config import get_config
 from app_security import is_safe_path
-from flask import Blueprint, jsonify, send_from_directory
+from flask import Blueprint, jsonify, request, send_from_directory
 from flask_login import current_user, login_required
 from PIL import Image, ImageOps
 from services.client_log import log_to_client
@@ -100,6 +100,27 @@ def _remove_thumbnail(filename: str) -> None:
         os.remove(thumb_path)
 
 
+def _parse_optional_pagination(default_limit: int = 24, *, max_limit: int = 100) -> tuple[int | None, int | None, bool]:
+    limit_raw = request.args.get("limit")
+    offset_raw = request.args.get("offset")
+    if (limit_raw is None) and (offset_raw is None):
+        return None, None, False
+
+    try:
+        limit = int(limit_raw if limit_raw is not None else default_limit)
+    except (ValueError, TypeError):
+        limit = default_limit
+    limit = max(1, min(limit, max_limit))
+
+    try:
+        offset = int(offset_raw if offset_raw is not None else 0)
+    except (ValueError, TypeError):
+        offset = 0
+    offset = max(0, offset)
+
+    return limit, offset, True
+
+
 @api_screenshots_bp.route("/api/screenshots", methods=["GET"])
 @login_required
 def get_screenshots():
@@ -128,6 +149,12 @@ def get_screenshots():
         for item in screenshots:
             item.pop("_created_ts", None)
 
+        limit, offset, paged = _parse_optional_pagination(default_limit=24, max_limit=100)
+        if paged:
+            total = len(screenshots)
+            items = screenshots[offset : offset + limit]
+            return jsonify({"items": items, "total": total, "limit": limit, "offset": offset})
+
         return jsonify(screenshots)
     except Exception as e:
         return jsonify({"error": str(e)}), 500