feat: API Key 系统 — CRUD + panel_auth 集成 + 持久化

新增:
- services/web_panel/routes/apikeys.py — 创建/列表/删除 API Key
- panel_auth() 双重验证: Session Store → API Key fallback
- _check_plugin_auth() 支持 API Key
- API Key 持久化到 SenSuDB (config_kv 表)
- 格式: sk- + 48 hex chars
- 脱敏显示 (前8后4)
- 删除后立即失效 (401)

WebPanelManager 注册 apikeys 路由

Co-Authored-By: Claude <noreply@anthropic.com>

services/web_panel/manager.py

@@ -7,7 +7,7 @@ import hashlib
 import secrets
 from pathlib import Path
 from aiohttp import web
-from .routes import auth, status, plugins, commands, logs, projects, proxy, plugin_web, files
+from .routes import auth, status, plugins, commands, logs, projects, proxy, plugin_web, files, apikeys
 
 logger = logging.getLogger(__name__)
 
@@ -78,6 +78,7 @@ class WebPanelManager:
         
         # 注册 API 路由
         auth.setup_routes(app, self.base_path)
+        apikeys.setup_routes(app, self.base_path)
         status.setup_routes(app, self.base_path)
         plugins.setup_routes(app, self.base_path)
         commands.setup_routes(app, self.base_path)