fix(auth): transfer WeChat id on merge; stop false phone prompts

Merge used to drop wxOpenId so OAuth created a new guest without phone every time. Now migrate WeChat identity, recover legacy merged openIds, return accountMerged and force page reload, and only soft-prompt when phone is truly unbound.

apps/mini-user/src/lib/auth-nav.ts

@@ -70,3 +70,46 @@ export function finishLoginNavigate(returnTo?: string) {
 
   Taro.reLaunch({ url: '/pages/home/index' });
 }
+
+/**
+ * 账号合并后强制整页刷新，避免旧会话栈 / 旧用户缓存继续提示绑定手机号。
+ * H5：按当前路径推算出落地 URL 后 location.replace；小程序：reLaunch。
+ */
+export function forceReloadAfterAccountMerge(returnTo?: string) {
+  const raw = (returnTo || '').trim();
+  let target = '';
+  try {
+    target = raw ? decodeURIComponent(raw) : '';
+  } catch {
+    target = raw;
+  }
+  const pathOnly = target.split('?')[0];
+  const safePath =
+    pathOnly && pathOnly.startsWith('/pages/') && !pathOnly.includes('/pages/login')
+      ? target
+      : '/pages/home/index';
+  const launchPath = safePath.split('?')[0];
+
+  if (process.env.TARO_ENV === 'h5' && typeof window !== 'undefined') {
+    const { origin, pathname, search } = window.location;
+    const marker = '/pages/';
+    const idx = pathname.indexOf(marker);
+    let href: string;
+    if (idx >= 0) {
+      href = `${origin}${pathname.slice(0, idx)}${safePath}`;
+    } else if (window.location.hash.includes('/pages/')) {
+      href = `${origin}${pathname}${search}#${safePath}`;
+    } else {
+      const base = pathname.replace(/\/$/, '') || '';
+      href = `${origin}${base}${safePath.startsWith('/') ? safePath : `/${safePath}`}`;
+    }
+    window.location.replace(href);
+    return;
+  }
+
+  if (TAB_PAGES.has(launchPath)) {
+    Taro.reLaunch({ url: launchPath });
+    return;
+  }
+  Taro.reLaunch({ url: safePath.startsWith('/') ? safePath : `/${safePath}` });
+}