fix: final review findings - thread safety, xss, cache

app/src/main/java/top/yeij/hearth/webview/JsBridge.kt

@@ -75,8 +75,10 @@ class JsBridge(
             Log.d("HearthBridge", "openWebApp: unknown id=$id")
             return
         }
-        container.open(id, app.url, app.name)
+        // 状态变更与 View 变更统一在主线程串行，避免与 onBackPressed/listTabs 并发读写
+        // Mutate tab state and view on the main thread together, serializing access
         onMain {
+            container.open(id, app.url, app.name)
             host.openWebView(id, app.url)
             host.syncTabs(container.tabs())
         }
@@ -90,14 +92,14 @@ class JsBridge(
     fun closeWebApp(id: String) {
         val container = webAppContainer ?: return
         val host = webAppHost ?: return
-        container.close(id)
-        val nextActiveId = container.activeTabId()
         onMain {
+            container.close(id)
+            val nextActiveId = container.activeTabId()
             host.closeWebView(id)
             nextActiveId?.let { host.switchWebView(it) }
             host.syncTabs(container.tabs())
+            Log.d("HearthBridge", "closeWebApp: id=$id remaining=${container.tabs().size}")
         }
-        Log.d("HearthBridge", "closeWebApp: id=$id remaining=${container.tabs().size}")
     }
 
     // 切换激活标签：校验 id 存在后更新状态 → 主线程切换 WebView 可见性 → 同步顶栏
@@ -107,10 +109,11 @@ class JsBridge(
     fun switchTab(id: String) {
         val container = webAppContainer ?: return
         val host = webAppHost ?: return
-        if (!container.switchTo(id)) return
         onMain {
-            host.switchWebView(id)
-            host.syncTabs(container.tabs())
+            if (container.switchTo(id)) {
+                host.switchWebView(id)
+                host.syncTabs(container.tabs())
+            }
         }
         Log.d("HearthBridge", "switchTab: id=$id")
     }
@@ -153,12 +156,15 @@ class JsBridge(
         Log.d("HearthBridge", "webReload called")
     }
 
-    // 清单内存缓存：首次拉取后缓存，后续复用（避免 openWebApp 重复 I/O）
-    // In-memory manifest cache: fetch once, reuse afterwards (avoid repeated I/O)
+    // 清单内存缓存：首次拉取成功后缓存，后续复用（避免 openWebApp 重复 I/O）
+    // 空结果（离线失败）不缓存，下次调用重试拉取，避免空清单被永久缓存
+    // In-memory manifest cache: cache only on a successful non-empty fetch (avoid
+    // repeated I/O); empty results (offline failure) are never cached so the next
+    // call retries instead of being permanently stuck with an empty manifest
     private fun manifest(): List<WebApp> {
         manifestCache?.let { return it }
         val apps = webAppRepository?.fetchManifest() ?: emptyList<WebApp>()
-        manifestCache = apps
+        if (apps.isNotEmpty()) manifestCache = apps
         return apps
     }