feat: 添加文件发现系统页面及相关文档

docs: 更新导航和页面数量统计
refactor: 在多个页面添加设计哲学章节

Author: tt-a1i

src/App.tsx

@@ -114,6 +114,7 @@ const TurnStateMachine = lazy(() => import('./pages/TurnStateMachine').then(m =>
 const TokenAccountingSystem = lazy(() => import('./pages/TokenAccountingSystem').then(m => ({ default: m.TokenAccountingSystem })));
 const SessionPersistence = lazy(() => import('./pages/SessionPersistence').then(m => ({ default: m.SessionPersistence })));
 const ToolDeveloperGuide = lazy(() => import('./pages/ToolDeveloperGuide').then(m => ({ default: m.ToolDeveloperGuide })));
+const FileDiscovery = lazy(() => import('./pages/FileDiscovery').then(m => ({ default: m.FileDiscovery })));
 const CoreCode = lazy(() => import('./pages/CoreCode').then(m => ({ default: m.CoreCode })));
 const LoopMechanism = lazy(() => import('./pages/LoopMechanism').then(m => ({ default: m.LoopMechanism })));
 
@@ -248,6 +249,8 @@ function App() {
         return <ToolReference />;
       case 'tool-dev-guide':
         return <ToolDeveloperGuide />;
+      case 'file-discovery':
+        return <FileDiscovery />;
       case 'tool-scheduler':
         return <ToolSchedulerDetails />;
       case 'tool-arch':

src/nav.ts

@@ -55,6 +55,7 @@ export const navGroups: NavGroup[] = [
       { id: 'tool-ref', label: '工具参考', highlight: true },
       { id: 'tool-dev-guide', label: '工具开发指南', highlight: true },
       { id: 'tool-scheduler', label: '工具调度详解', highlight: true },
+      { id: 'file-discovery', label: '文件发现系统', highlight: true },
       { id: 'tool-arch', label: '工具架构' },
       { id: 'tool-detail', label: '工具执行' },
       { id: 'ai-tool', label: 'AI工具交互' },