feat(web): add login page for desktop auth callback

- Add email/code login with verification
- Add Google OAuth login
- Add desktop callback API route
- Add request service with device ID handling

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/app/api/desktop/session/route.ts

@@ -0,0 +1,23 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+/**
+ * Desktop Session API
+ *
+ * 参考：Cap/apps/web/app/api/desktop/[...route]/session.ts
+ *
+ * 流程：
+ * 1. Desktop 打开这个 URL（带 port 或 platform 参数）
+ * 2. 直接重定向到 /login?next=当前URL
+ * 3. 用户登录后，login 页面会重定向到 Desktop 回调
+ *
+ * 注意：Web 端不做任何 SID 缓存，每次都要重新登录
+ */
+export async function GET(request: NextRequest) {
+  // Build current URL for next parameter
+  const currentUrl = request.nextUrl.toString();
+
+  // Always redirect to login page - no caching, always require fresh login
+  const loginUrl = new URL('/login', request.nextUrl.origin);
+  loginUrl.searchParams.set('next', currentUrl);
+  return NextResponse.redirect(loginUrl);
+}