feat: 新增流程总览图页面及导航功能

添加流程总览图页面，包含五组十域可交互SVG流程图，支持模块点击跳转至对应流程详情页。同时在侧边栏和首页添加导航入口，优化流程详情页的返回逻辑和布局样式。

src/components/layout/Layout.tsx

@@ -30,9 +30,7 @@ export function Layout({ children }: LayoutProps) {
               sidebarOpen ? 'lg:ml-64' : 'lg:ml-20'
             )}
           >
-            <div className="mx-auto max-w-7xl">
-              {children}
-            </div>
+            {children}
           </main>
         </div>
       </div>

src/components/layout/Sidebar.tsx

@@ -6,6 +6,7 @@ import {
   BookOpen,
   Layers,
   LayoutGrid,
+  Workflow,
   Share2,
   Settings,
   ChevronLeft,
@@ -15,6 +16,7 @@ import {
 const navItems = [
   { path: '/', label: '首页', icon: Home },
   { path: '/process-matrix', label: '49过程矩阵', icon: LayoutGrid },
+  { path: '/process-roadmap', label: '流程总览图', icon: Workflow },
   { path: '/knowledge-areas', label: '知识领域', icon: BookOpen },
   { path: '/process-groups', label: '过程组', icon: Layers },
   { path: '/process-graph', label: '过程关系图', icon: Share2 },