feat: restore API文档 nav item (iframe /docs) without touching other 4 modules

webapp/static/index.html

@@ -28,6 +28,9 @@
         <button class="nav-item" data-view="profiles">
           <span class="nav-ico">⚙</span><span>LLM 配置</span>
         </button>
+        <button class="nav-item" data-view="apidocs">
+          <span class="nav-ico">⎔</span><span>API 文档</span>
+        </button>
       </nav>
       <div class="sidebar-foot">
         <span class="dot" id="health-dot"></span>
@@ -212,6 +215,17 @@
           <p class="muted">点击「新建配置」添加第一个。</p>
         </div>
       </section>
+
+      <!-- API 文档视图 -->
+      <section class="view" id="view-apidocs" hidden>
+        <iframe
+          id="apidocs-frame"
+          src="/docs"
+          class="apidocs-frame"
+          title="API 文档"
+          allowfullscreen>
+        </iframe>
+      </section>
     </main>
   </div>