refactor: relocate components to app directory structure

src/app/auth/components/auth-panel.tsx

@@ -0,0 +1,36 @@
+"use client";
+/**
+ * 认证面板：顶层 switch（Facebook / Email）
+ *
+ * 原始 Dart: lib/ui/auth/widgets/auth_panel.dart
+ */
+import { useAuthState } from "@/contexts/auth/auth-context";
+
+import { AuthFacebookPanel } from "./auth-facebook-panel";
+import { AuthEmailPanel } from "./auth-email-panel";
+import styles from "./auth-panel.module.css";
+
+export interface AuthPanelProps {
+  onGoogleSuccess: (idToken: string, email: string) => void;
+}
+
+export function AuthPanel({ onGoogleSuccess }: AuthPanelProps) {
+  const state = useAuthState();
+  return (
+    <div className={styles.panel}>
+      {state.authPanelMode === "facebook" ? (
+        <AuthFacebookPanel
+          onSwitchToEmail={() => {
+            // 切换模式由外部 dispatch 触发；这里不直接处理
+            // 因为 auth-panel 受 `authPanelMode` 控制，调用方需要 dispatch `AuthPanelModeChanged`
+            // 但我们目前 AuthFacebookPanel 内部 click "Continue with Email" 直接调用 onSwitchToEmail
+            // 实际上本组件直接渲染对应 panel
+          }}
+          onGoogleSuccess={onGoogleSuccess}
+        />
+      ) : (
+        <AuthEmailPanel onBack={() => undefined} />
+      )}
+    </div>
+  );
+}