feat: OAuth 登录后返回来源页 + 登录页清理

- OAuth 流程透传 redirect 参数，登录后回到触发页面而非固定跳 Dashboard
- 服务端校验 redirect 为相对路径，防止 Open Redirect 攻击
- 隐藏 Apple 登录按钮和邮箱注册入口
- Dark Mode 切换改为下拉菜单样式
- 提取 useClickOutside hook 消除重复代码

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/web/src/components/ThemeToggle.tsx

@@ -1,46 +1,82 @@
+import { useState, useRef, useCallback } from 'react';
 import { useTheme } from '../lib/theme';
 import { useI18n, type TranslationKey } from '../lib/i18n';
+import { useClickOutside } from '../hooks/useClickOutside';
 
-const icons = {
-  light: (
-    <svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-      <circle cx="12" cy="12" r="5" /><path d="M12 1v2m0 18v2M4.22 4.22l1.42 1.42m12.72 12.72l1.42 1.42M1 12h2m18 0h2M4.22 19.78l1.42-1.42M18.36 5.64l1.42-1.42" />
-    </svg>
-  ),
-  dark: (
-    <svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-      <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z" />
-    </svg>
-  ),
-  system: (
-    <svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-      <rect x="2" y="3" width="20" height="14" rx="2" /><path d="M8 21h8m-4-4v4" />
-    </svg>
-  ),
-};
-
-const order: Array<'light' | 'dark' | 'system'> = ['light', 'dark', 'system'];
+const themes: Array<{ key: 'light' | 'dark' | 'system'; icon: JSX.Element }> = [
+  {
+    key: 'light',
+    icon: (
+      <svg className="w-3.5 h-3.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+        <circle cx="12" cy="12" r="5" /><path d="M12 1v2m0 18v2M4.22 4.22l1.42 1.42m12.72 12.72l1.42 1.42M1 12h2m18 0h2M4.22 19.78l1.42-1.42M18.36 5.64l1.42-1.42" />
+      </svg>
+    ),
+  },
+  {
+    key: 'dark',
+    icon: (
+      <svg className="w-3.5 h-3.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+        <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z" />
+      </svg>
+    ),
+  },
+  {
+    key: 'system',
+    icon: (
+      <svg className="w-3.5 h-3.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+        <rect x="2" y="3" width="20" height="14" rx="2" /><path d="M8 21h8m-4-4v4" />
+      </svg>
+    ),
+  },
+];
 
 export default function ThemeToggle() {
   const { theme, setTheme } = useTheme();
   const { t } = useI18n();
+  const [open, setOpen] = useState(false);
+  const ref = useRef<HTMLDivElement>(null);
+  useClickOutside(ref, useCallback(() => setOpen(false), []), open);
+
+  const current = themes.find(th => th.key === theme)!;
 
   return (
-    <div className="flex items-center gap-1 p-1 rounded-lg bg-bg-tertiary">
-      {order.map((key) => (
-        <button
-          key={key}
-          onClick={() => setTheme(key)}
-          title={t(`theme.${key}` as TranslationKey)}
-          className={`flex items-center justify-center w-8 h-7 rounded-md transition-all duration-150 ${
-            theme === key
-              ? 'bg-bg-elevated text-text-primary shadow-sm'
-              : 'text-text-muted hover:text-text-secondary'
-          }`}
+    <div ref={ref} className="relative">
+      <button
+        onClick={() => setOpen(!open)}
+        className="flex items-center gap-1 px-2 py-1.5 rounded-lg text-xs font-medium transition-all duration-150 cursor-pointer hover:bg-bg-tertiary"
+        style={{ color: 'var(--text-secondary)' }}
+        aria-label="Switch theme"
+      >
+        {current.icon}
+      </button>
+
+      {open && (
+        <div
+          className="absolute top-full right-0 mt-1.5 min-w-[140px] rounded-xl py-1 z-50 animate-slide-down"
+          style={{
+            background: 'var(--bg-elevated)',
+            border: '1px solid var(--border-default)',
+            boxShadow: 'var(--shadow-lg)',
+          }}
         >
-          {icons[key]}
-        </button>
-      ))}
+          {themes.map(th => (
+            <button
+              key={th.key}
+              onClick={() => { setTheme(th.key); setOpen(false); }}
+              className="flex items-center gap-2.5 w-full px-3 py-2 text-[13px] transition-colors cursor-pointer rounded-lg mx-0.5"
+              style={{
+                width: 'calc(100% - 4px)',
+                color: theme === th.key ? 'var(--text-primary)' : 'var(--text-secondary)',
+                fontWeight: theme === th.key ? 500 : 400,
+                background: theme === th.key ? 'var(--bg-tertiary)' : 'transparent',
+              }}
+            >
+              <span className="leading-none">{th.icon}</span>
+              {t(`theme.${th.key}` as TranslationKey)}
+            </button>
+          ))}
+        </div>
+      )}
     </div>
   );
 }