refactor: 移除 Dashboard 页面及相关功能，更新路由和组件逻辑

- 移除 Dashboard 相关的组件、特性和测试代码，简化项目结构。
- 更新 PageSkeleton 组件，默认渲染工具页面骨架。
- 修改 RouterContainer 和 RouterProvider 以适应新的默认路由策略，确保用户直接访问 timestamp 页面。
- 更新测试用例，确保在新结构下的功能正常。

src/layout/FeatureNav/__tests__/resolveNavFeatures.test.ts

@@ -0,0 +1,58 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import * as featureConfig from '@/config/features';
+import { resolveNavFeatures } from '../resolveNavFeatures';
+
+describe('resolveNavFeatures', () => {
+  beforeEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('应按 keys 顺序返回可见工具', () => {
+    const items = resolveNavFeatures(['jwt', 'timestamp'], ['timestamp', 'jwt']);
+
+    expect(items.map((item) => item.key)).toEqual(['jwt', 'timestamp']);
+    expect(items.map((item) => item.feature.label)).toEqual(['JWT 解析', '时间戳']);
+  });
+
+  it('缺少 themeColorKey 但有 icon 的工具仍应显示', () => {
+    const originalGetFeatureByKey = featureConfig.getFeatureByKey;
+    vi.spyOn(featureConfig, 'getFeatureByKey').mockImplementation((key) => {
+      const feature = originalGetFeatureByKey(key);
+      if (key === 'timestamp' && feature) {
+        return { ...feature, themeColorKey: undefined };
+      }
+      return feature;
+    });
+
+    const items = resolveNavFeatures(['timestamp'], ['timestamp']);
+
+    expect(items.map((item) => item.key)).toEqual(['timestamp']);
+  });
+
+  it('应过滤不在 visiblePages 中的工具', () => {
+    const items = resolveNavFeatures(['jwt', 'timestamp'], ['timestamp']);
+
+    expect(items.map((item) => item.key)).toEqual(['timestamp']);
+  });
+
+  it('visiblePages 无匹配工具时应返回空列表', () => {
+    const items = resolveNavFeatures(['jwt', 'timestamp'], []);
+
+    expect(items).toEqual([]);
+  });
+
+  it('应过滤缺少 icon 的工具', () => {
+    const originalGetFeatureByKey = featureConfig.getFeatureByKey;
+    vi.spyOn(featureConfig, 'getFeatureByKey').mockImplementation((key) => {
+      const feature = originalGetFeatureByKey(key);
+      if (key === 'jwt' && feature) {
+        return { ...feature, icon: undefined };
+      }
+      return feature;
+    });
+
+    const items = resolveNavFeatures(['jwt', 'timestamp'], ['jwt', 'timestamp']);
+
+    expect(items.map((item) => item.key)).toEqual(['timestamp']);
+  });
+});