fix: 审查阻塞修复 — SHA256 TBD占位+beta/nightly→stable+硬编码channel+路径校验

- manifest.json: beta/nightly h5.url → index-stable.html
- SHA256: TBD占位(build后push-hotfix.sh更新)
- index-stable: ver元素用channel变量, match?.[1]防御
- fetchText: 过滤..防止路径遍历

ota/h5/index-stable.html

@@ -72,5 +72,5 @@ function applyUpdate(){
  Android.saveCache(t);log('OK! restart app to apply')
 }
 function h5UrlRelative(u){var p=u.split('/ota/');return p.length>1?'h5/'+p[1].split('/h5/')[1]:u}
-document.getElementById('ver').innerText=Android.fetchManifest('stable').match(/"latest":"([^"]+)"/)[1];
+document.getElementById('ver').innerText=Android.fetchManifest(channel).match(/"latest":"([^"]+)"/)?.[1]||channel;
 </script></body></html>