feat: hash路由 + 插件页面内联加载 + 侧边栏插件面板展开项

- Hash路由: #/dashboard #/files #/plugins/xxx 支持刷新保持/前进后退
- 登录过期保留hash,登录后自动跳回原页面
- 插件WebUI页面内联加载到page-container(不再弹新窗)
- 插件页面HTML自动处理: style提取/body剥离/script执行/padding归零
- 侧边栏新增「插件面板」可折叠项,展开列出所有已注册插件页面
- 内存卡片显示 已用/总容量(百分比右侧)
- 插件开发指南新增 2.6 WebUI页面开发章节

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

static/web_panel/home.html

@@ -46,6 +46,19 @@
                 <svg width="20" height="20" viewBox="0 0 24 24"><path d="M20 6h-8l-2-2H4c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h16c1.1 0 2-.9 2-2V8c0-1.1-.9-2-2-2zm-1 4H5V8h14v2zm0 2v6H5v-6h14z"/></svg>
                 <span>文件管理</span>
             </a>
+
+            <!-- Plugin WebUI pages (collapsible) -->
+            <div class="nav-expandable" id="nav-plugins">
+                <div class="nav-expand-header" onclick="togglePluginPages()">
+                    <svg width="20" height="20" viewBox="0 0 24 24" style="flex-shrink:0"><path d="M20.5 11H19V7c0-1.1-.9-2-2-2h-4V3.5C13 2.12 11.88 1 10.5 1S8 2.12 8 3.5V5H4c-1.1 0-1.99.9-1.99 2v3.8H3.5c1.49 0 2.7 1.21 2.7 2.7s-1.21 2.7-2.7 2.7H2V20c0 1.1.9 2 2 2h3.8v-1.5c0-1.49 1.21-2.7 2.7-2.7 1.49 0 2.7 1.21 2.7 2.7V22H17c1.1 0 2-.9 2-2v-4h1.5c1.38 0 2.5-1.12 2.5-2.5S21.88 11 20.5 11z"/></svg>
+                    <span style="flex:1">插件面板</span>
+                    <svg width="14" height="14" viewBox="0 0 24 24" id="nav-plugins-arrow" style="transition:transform .2s"><path d="M7 10l5 5 5-5z"/></svg>
+                </div>
+                <div class="nav-expand-body" id="nav-plugins-body" style="display:none">
+                    <div class="nav-expand-empty" style="padding:6px 16px;font-size:.75rem;color:var(--text-dim)">暂无插件面板</div>
+                </div>
+            </div>
+
             <div class="toggle-sidebar" onclick="toggleSidebar()">☰</div>
         </aside>
 
@@ -59,6 +72,6 @@
     <script src="./static/js/chart.js?v=0603"></script>
     
     <!-- 🟢 2. 再加载主逻辑 -->
-    <script src="./static/js/app.js?v=0601"></script>
+    <script src="./static/js/app.js?v=0700"></script>
 </body>
 </html>