feat: 全局用户头像徽章，所有页面右上角统一显示

- 新增 GlobalUserBadge 组件，固定在右上角，已登录显示头像+用户名，未登录显示登录按钮
- 通过 layout.tsx 全局挂载，仅在个人中心页隐藏
- userId.ts 登录/登出时派发 nowhatever_auth 事件，组件实时响应
- 移除各页面重复的用户指示器（首页、极速救场、周末契约大厅、个人中心顶栏退出按钮）
- TopNav 右侧留出空间避免与全局徽章重叠
- 头像徽章采用暗色主题风格（bg-surface/80）

src/app/panic/page.tsx

@@ -3,12 +3,10 @@
 import { useState, useRef, useEffect, useCallback } from "react";
 import { useRouter } from "next/navigation";
 import { motion, AnimatePresence } from "framer-motion";
-import { Plus, LogIn, Loader2, MapPin, Navigation, X, Users, Heart, Sparkles, ChevronRight, Flame, User, ArrowLeft } from "lucide-react";
-import { getUserId, getCachedProfile, getCachedPreferences } from "@/lib/userId";
-import { getAvatarBg } from "@/lib/avatars";
-import AuthModal from "@/components/AuthModal";
+import { Plus, LogIn, Loader2, MapPin, Navigation, X, Users, Heart, Sparkles, ChevronRight, Flame, ArrowLeft } from "lucide-react";
+import { getUserId, getCachedPreferences } from "@/lib/userId";
 import { SCENES, getSceneConfig } from "@/lib/sceneConfig";
-import type { UserProfile, SceneType } from "@/types";
+import type { SceneType } from "@/types";
 
 interface LocationSuggestion {
   id: string;
@@ -90,13 +88,7 @@ export default function PanicPage() {
   const [scene, setScene] = useState<SceneType>("eat");
   const sceneConfig = getSceneConfig(scene);
 
-  const [profile, setProfile] = useState<UserProfile | null>(null);
-  const [authModalOpen, setAuthModalOpen] = useState(false);
-
   useEffect(() => {
-    const cached = getCachedProfile();
-    if (cached) setProfile(cached);
-
     const prefs = getCachedPreferences();
     if (prefs.cuisine) setCuisine(prefs.cuisine);
     if (prefs.priceRange) setPriceRange(prefs.priceRange);
@@ -265,27 +257,6 @@ export default function PanicPage() {
         返回
       </button>
 
-      {/* Profile / Auth button */}
-      <div className="absolute right-4 top-3">
-        {profile ? (
-          <button
-            onClick={() => router.push("/profile")}
-            className={`flex h-8 items-center gap-1.5 rounded-full px-3 text-sm font-medium transition-colors active:opacity-80 ${getAvatarBg(profile.avatar)}`}
-          >
-            <span className="text-base leading-none">{profile.avatar}</span>
-            <span className="max-w-20 truncate text-xs font-semibold text-foreground">{profile.username}</span>
-          </button>
-        ) : (
-          <button
-            onClick={() => setAuthModalOpen(true)}
-            className="flex h-8 items-center gap-1.5 rounded-full bg-surface px-3 text-xs font-medium text-muted ring-1 ring-border transition-colors active:bg-elevated"
-          >
-            <User size={14} />
-            登录
-          </button>
-        )}
-      </div>
-
       <motion.div
         className="flex items-center gap-3"
         initial={{ y: -20, opacity: 0 }}
@@ -629,11 +600,6 @@ export default function PanicPage() {
         )}
       </motion.div>
 
-      <AuthModal
-        open={authModalOpen}
-        onClose={() => setAuthModalOpen(false)}
-        onAuth={(p) => setProfile(p)}
-      />
     </div>
   );
 }