fix(h5): 小程序 WebView 刘海区背景与顶栏安全区

Logo 下移 safe-area、embed 隐藏 HTML 标题；暖色渐变铺满刘海，页面背景上延与全屏洗底层对齐。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/user-h5/src/lib/mpEmbed.ts

@@ -1,6 +1,13 @@
 const MP_EMBED_KEY = 'yxg_mp_embed'
 const MP_QUERY = 'mp'
 
+/** Apply document-level embed chrome (safe-area wash, hide HTML title). */
+export function applyMpEmbedDom(): void {
+  if (typeof document === 'undefined' || !isMpEmbed()) return
+  document.title = '\u200b'
+  document.documentElement.classList.add('mp-embed')
+}
+
 /** Persist ?mp=1 from mini-program web-view entry. Call once before router mount. */
 export function initMpEmbed(): void {
   if (typeof window === 'undefined') return
@@ -8,6 +15,7 @@ export function initMpEmbed(): void {
   if (params.get(MP_QUERY) === '1') {
     sessionStorage.setItem(MP_EMBED_KEY, '1')
   }
+  applyMpEmbedDom()
 }
 
 /** True when H5 runs inside WeChat mini-program web-view (no H5 tab bar). */