Add SSL certificate management to WebUI config

Introduces backend API endpoints and frontend UI for managing SSL certificates, including viewing status, uploading, and deleting cert/key files. Adds a new SSL configuration tab in the dashboard, allowing users to enable HTTPS by providing PEM-formatted certificate and key, with changes taking effect after restart.

packages/napcat-webui-frontend/src/pages/dashboard/config/index.tsx

@@ -10,6 +10,7 @@ import ChangePasswordCard from './change_password';
 import LoginConfigCard from './login';
 import OneBotConfigCard from './onebot';
 import ServerConfigCard from './server';
+import SSLConfigCard from './ssl';
 import ThemeConfigCard from './theme';
 import WebUIConfigCard from './webui';
 
@@ -81,6 +82,11 @@ export default function ConfigPage () {
             <ServerConfigCard />
           </ConfigPageItem>
         </Tab>
+        <Tab title='SSL配置' key='ssl'>
+          <ConfigPageItem size='sm'>
+            <SSLConfigCard />
+          </ConfigPageItem>
+        </Tab>
         <Tab title='WebUI配置' key='webui'>
           <ConfigPageItem>
             <WebUIConfigCard />