fix: harden workbench sidebar resizing

Merge #348: add right hardware sidebar resize state and expand source/build Playwright layout coverage for #278 without changing M3 control paths or claiming DEV-LIVE hardware acceptance.

web/hwlab-cloud-web/index.html

@@ -176,7 +176,20 @@
         </form>
       </section>
 
-      <aside class="right-sidebar" aria-label="运行状态与可信记录">
+      <aside class="right-sidebar" id="hardware-sidebar" aria-label="运行状态与可信记录">
+        <div
+          class="resize-handle right-sidebar-resize"
+          id="right-sidebar-resize"
+          role="separator"
+          tabindex="0"
+          aria-label="拖拽调整右侧硬件状态栏宽度"
+          aria-controls="hardware-sidebar"
+          aria-orientation="vertical"
+          aria-valuemin="560"
+          aria-valuemax="760"
+          aria-valuenow="620"
+          title="拖拽调整右侧硬件状态栏宽度；用左右方向键微调，Home/End 到最小或最大。"
+        ></div>
         <section class="hardware-status">
           <div class="panel-title-row">
             <div>