桌面 GUI 外链修复 + 主题顺序调整（含结构扁平化进行中的工作区基线）

- 集成 tauri-plugin-opener：Cargo/lib.rs/capabilities/npm 四处接线，新增 src/openExternal.ts（桌面走 opener，浏览器回退 window.open，相对路径绝对化）
- 关于页 4 个链接、活动栏官网菜单、代理错误横幅 2 处健康检查链接全部改走 openExternal，桌面端可正常跳转
- 设置→外观 主题顺序调整为 深色/浅色/跟随系统
- release 二进制重编并验证（浏览器实测关于页链接可开文档页）
- 附带工作区中未提交的扁平化重构现状（另一会话进行中）
- homepage 落地页与文档终检通过（8787 / 与 /docs 双 200）

src/App.tsx

@@ -0,0 +1,85 @@
+import { MockView } from "./features/mock/MockView";
+import { DocsView } from "./features/docs/DocsView";
+import { useWorkspaceLifecycle } from "./features/workspace/useWorkspaceLifecycle";
+/**
+ * OpsxAPI 工作台入口：组装顶栏 / 侧栏 / 标签页 / 编辑器 / 对话框。
+ */
+import { findNode } from "./core/index";
+import { useWorkspace } from "./workspaceStore";
+import { ActivityRail } from "./components/ActivityRail";
+import { Sidebar } from "./components/Sidebar";
+import { TestingView } from "./features/testing/TestingView";
+import { TabBar } from "./components/TabBar";
+import { TopBar } from "./components/TopBar";
+import { GraphqlEditor } from "./components/editors/GraphqlEditor";
+import { HttpEditor } from "./components/editors/HttpEditor";
+import { MqttEditor } from "./components/editors/MqttEditor";
+import { SocketIoEditor } from "./components/editors/SocketIoEditor";
+import { SseEditor } from "./components/editors/SseEditor";
+import { WebsocketEditor } from "./components/editors/WebsocketEditor";
+import { WorkspaceDialogs } from "./features/workspace/WorkspaceDialogs";
+import { EmptyState } from "./features/workspace/EmptyState";
+
+export function OpsxWorkspace() {
+  useWorkspaceLifecycle();
+  const inited = useWorkspace((s) => s.collections.length > 0 || s.environments.length > 0);
+  const collections = useWorkspace((s) => s.collections);
+  const activeTabId = useWorkspace((s) => s.activeTabId);
+  const toast = useWorkspace((s) => s.toast);
+  const clearToast = useWorkspace((s) => s.clearToast);
+  const view = useWorkspace((s) => s.view);
+
+  const activeRef = activeTabId ? findNode(collections, activeTabId) : null;
+  const activeNode = activeRef?.node;
+
+  return (
+    <div className="flex h-screen flex-col overflow-hidden">
+      <TopBar />
+      <div className="flex min-h-0 min-w-0 flex-1">
+      <ActivityRail />
+      {view === "docs" ? <DocsView /> : view === "mock" ? <MockView /> : view === "testing" ? (
+        <div className="flex min-h-0 min-w-0 flex-1">
+          <TestingView />
+        </div>
+      ) : (
+      <div className="flex min-h-0 min-w-0 flex-1">
+        <Sidebar />
+        <main className="flex min-w-0 flex-1 flex-col">
+          <TabBar />
+          {inited && activeNode === undefined && (
+            <EmptyState />
+          )}
+          {activeNode && activeNode.type === "request" && (
+            <>
+              {activeNode.kind === "http" && <HttpEditor node={activeNode} />}
+              {activeNode.kind === "graphql" && <GraphqlEditor node={activeNode} />}
+              {activeNode.kind === "websocket" && <WebsocketEditor node={activeNode} />}
+              {activeNode.kind === "sse" && <SseEditor node={activeNode} />}
+              {activeNode.kind === "socketio" && <SocketIoEditor node={activeNode} />}
+              {activeNode.kind === "mqtt" && <MqttEditor node={activeNode} />}
+            </>
+          )}
+          {activeNode && activeNode.type === "folder" && (
+            <EmptyState />
+          )}
+        </main>
+      </div>
+
+      )}
+      </div>
+      <WorkspaceDialogs />
+
+      {toast && (
+        <div
+          className="ops-toast"
+          role="status"
+          data-tone={toast.tone}
+          onClick={() => clearToast()}
+        >
+          {toast.message}
+        </div>
+      )}
+
+    </div>
+  );
+}