refactor: 侧边栏折叠按钮从 Header 移至侧边栏底部

- 移除 Header 左侧折叠按钮，改用 TDesign Menu operations 渲染底部折叠按钮
- Header 品牌名与版本号使用 brand-group 基线对齐
- 侧边栏折叠宽度从 80px 对齐 TDesign 默认 64px
- 更新相关测试和 DEVELOPMENT.md 文档

tests/web/App.test.tsx

@@ -44,4 +44,21 @@ describe("App", () => {
     expect(screen.getAllByText("用户管理").length).toBeGreaterThan(0);
     expect(screen.getAllByText("系统设置").length).toBeGreaterThan(0);
   });
+
+  test("Header 不包含侧边栏折叠按钮", () => {
+    window.fetch = (async () => {
+      return new Response(
+        JSON.stringify({ ok: true, service: "test-app", timestamp: new Date().toISOString(), version: "0.1.0" }),
+        {
+          headers: { "Content-Type": "application/json" },
+          status: 200,
+        },
+      );
+    }) as unknown as typeof fetch;
+
+    renderWithProviders(createElement(App));
+
+    const toggleButtons = document.querySelectorAll(".app-sidebar-toggle");
+    expect(toggleButtons.length).toBe(0);
+  });
 });