feat: inline nav editor in workspace + styled type tabs

- 外观与设计: nav edit button opens modal directly in workspace,
  no page editor redirect needed; add/remove/reorder/edit nav items
  with save-draft + publish buttons
- 内容与页面: type tabs now use segmented-control design (active
  blue pill group with counts) instead of scattered buttons

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

app/templates/workspace.html

@@ -57,4 +57,5 @@
 <div class="modal-actions"><button type="button" data-close="siteModal" class="btn btn-muted">取消</button><button type="button" id="createBack" class="btn btn-muted" hidden>上一步</button><button type="button" id="createNext" class="btn btn-primary">下一步：选择风格 →</button><button type="submit" id="createSubmit" class="btn btn-primary" hidden>确认创建网站</button></div>
 </form></dialog>
 <dialog id="entryModal" class="modal"><form id="entryForm" class="modal-inner"><div class="modal-top"><div><p class="overline">SITE CONTENT</p><h2 id="entryModalTitle">添加内容</h2><p class="subtle">按业务填写信息即可。详细布局可以进入可视化编辑器修改。</p></div><button type="button" data-close="entryModal" class="x-btn" aria-label="关闭">×</button></div><input type="hidden" name="entry_id"><div class="form-fields"><label>内容类型<select name="type"><option value="page">网站页面</option><option value="product">产品</option><option value="vehicle">车型</option><option value="post">新闻文章</option><option value="brand">品牌</option><option value="case">案例</option><option value="service">服务项目</option></select></label><label>状态<select name="status"><option value="published">可参与网站构建</option><option value="draft">内容草稿</option></select></label><label class="full">标题<input name="title" required maxlength="250" placeholder="输入页面或产品标题"></label><label class="full">页面地址 <span class="optional">新内容可留空</span><input name="route" placeholder="/products/example/"></label><label class="full">简短介绍<textarea name="summary" rows="2" placeholder="显示在列表和摘要中的介绍"></textarea></label><label class="full">正文内容 <span class="optional">可选</span><textarea name="body" rows="5" placeholder="填写业务正文，复杂排版请使用可视化设计器"></textarea></label><details class="form-expand full"><summary>SEO 设置（进阶）</summary><div class="form-fields"><label class="full">SEO 标题<input name="seo_title" placeholder="默认使用内容标题"></label><label class="full">Meta 描述<textarea name="seo_description" rows="2"></textarea></label></div></details></div><div class="modal-actions"><button type="button" data-close="entryModal" class="btn btn-muted">取消</button><button type="submit" class="btn btn-primary">保存内容</button></div></form></dialog>
+<dialog id="navModal" class="modal" style="width:640px"><div class="modal-inner"><div class="modal-top"><div><p class="overline">NAVIGATION</p><h2>☰ 编辑导航菜单</h2><p class="subtle">直接修改菜单文字和链接。保存后需重新构建网站才能生效。</p></div><button type="button" data-close="navModal" class="x-btn" aria-label="关闭">×</button></div><div id="navEditorBody" style="min-height:120px"><p class="muted">加载中…</p></div><button type="button" class="nav-add-btn" onclick="W.addNavItem()">＋ 添加菜单项</button><div class="nav-edit-actions"><button type="button" data-close="navModal" class="btn btn-muted">取消</button><button type="button" class="btn" onclick="W.saveNavDraft()">保存草稿</button><button type="button" class="btn btn-primary" onclick="W.publishNav()">发布导航</button></div></div></dialog>
 </body></html>