feat: Add source code viewer with Gitea integration

- Add /source page with file explorer and code viewer
- Connect to Gitea API for repository browsing
- Implement MCP tools: get_repo_info, list_repo_files, read_repo_file, search_repo_code
- Default to nucleo000/agent-ui repository
- Support branch switching and file search

frontend/src/router/index.ts

@@ -38,6 +38,11 @@ const router = createRouter({
       path: '/database',
       name: 'database',
       component: () => import('../pages/DatabasePage.vue')
+    },
+    {
+      path: '/source',
+      name: 'source',
+      component: () => import('../pages/SourceCodePage.vue')
     }
   ]
 })