polish(web): 打磨 Web 会话界面的布局、自适应与组件一致性

1. 统一会话列宽度轴：新增 --dsh-chat-content-width（748px），输入框、todo、goal、queue、approval、plan review、ask question 等容器的宽度与边距全部由该变量推导，消除各面板之间的像素漂移，窄视口下的边缘留白也保持一致。
2. 输入框自适应与细节：控制行改为容器查询（460px 阈值以下权限选择器只显示图标+下拉，隐藏文字）；卡片圆角 20→22、行内边距调整并整体下移 2px（发送按钮除外）；permission/model 触发器统一 24px 圆角；Plan 与 Read Only 间距 +8。
3. 修复浮层菜单溢出：slash 菜单与命令弹层钳制到输入卡片宽度，超长行以省略号截断；Tooltip 增加 12px 视口边缘安全距离。
4. 增加与替换图标：Add provider 改用输入框同款加号图标（IconPlusOutline16），统一图标尺寸与字号。
5. 统一 Settings → Models 组件：补齐按钮 hover 态、select 下拉箭头不再贴边、标题区与 provider 卡片间距 +12。
6. 侧边栏交互：add workspace / group by / create session / 收起侧边栏四个图标按钮增加 500ms 延迟 tooltip（前两个向下弹出）；展开态的 New Session 不再重复显示 tooltip；侧边栏窄屏自适应收起逻辑微调。
7. 其他：hero 区 workspace 徽章右移对齐；附带 Agent Note（中英双语）记录共享宽度轴与容器查询的设计取舍。

packages/client/ui-question/src/client/PlanReviewPanel.module.css

@@ -9,7 +9,9 @@
 .frame {
   display: flex;
   justify-content: center;
-  padding: 6px 24px 10px;
+  /* Sides = clearance + 16px: the card lands on the shared content width
+     (input card - 32) at every viewport. */
+  padding: 6px calc(var(--dsh-composer-side-clearance) + 16px) 10px;
 }
 
 .card {
@@ -17,7 +19,7 @@
   overflow: hidden;
   flex-direction: column;
   width: 100%;
-  max-width: 776px;
+  max-width: var(--dsh-chat-content-width);
   /* Composer seat sits in a fixed-height conversation column (overflow
      hidden): cap the card against the viewport and scroll the plan, so the
      strip and the decision row stay reachable on a long plan. */
@@ -93,6 +95,18 @@
   gap: 8px;
 }
 
+/* The discuss verb stays a quiet text button beside the two decision
+   capsules: 14px glyph against the 14px label with a slightly wider gap, so
+   the icon reads as a prefix rather than a peer-sized control. */
+.discuss {
+  gap: 6px;
+  color: var(--dsw-alias-label-secondary);
+}
+
+.discuss:hover:not(:disabled) {
+  color: var(--dsw-alias-label-primary);
+}
+
 @media (max-width: 720px) {
   .frame {
     padding: 6px 10px 10px;

packages/client/ui-question/src/client/PlanReviewPanel.tsx

@@ -73,21 +73,21 @@ export function PlanReviewPanel({ pending, review, t }: PlanReviewPanelProps) {
           <div className={css.feedback} role="status">{error}</div>
           <div className={css.actions}>
             <Button
-              size="sm" variant="ghost" icon={<IconEditOutline16 />}
+              variant="ghost" className={css.discuss} icon={<IconEditOutline16 size={14} />}
               disabled={busy} onClick={() => { settle(() => pending.cancel()) }}
             >
               {t('plan.discuss')}
             </Button>
             {decline !== undefined && (
               <Button
-                size="sm" variant="outline" {...tooltip(decline.description)}
+                variant="outline" {...tooltip(decline.description)}
                 disabled={busy} onClick={() => { decide(decline.label) }}
               >
                 {t('plan.decline')}
               </Button>
             )}
             <Button
-              size="sm" variant="primary" {...tooltip(review.approve.description)}
+              variant="primary" {...tooltip(review.approve.description)}
               disabled={busy} onClick={() => { decide(review.approve.label) }}
             >
               {t('plan.approve')}

packages/client/ui-question/src/client/QuestionComposer.module.css

@@ -1,9 +1,10 @@
-/* The takeover seats where the input card sits, so the frame mirrors the
-   InputBar geometry (side pad 32, card cap 800) to keep both edges flush. */
+/* The takeover seats where the input card sits, centered on the InputBar
+   axis at the shared content width (input card - 32): sides = clearance +
+   16px so the relation also holds on narrow viewports. */
 .frame {
   display: flex;
   justify-content: center;
-  padding: 6px 32px 10px;
+  padding: 6px calc(var(--dsh-composer-side-clearance) + 16px) 10px;
 }
 
 /* Figma Input 973:36348 body over the 1019:36938 header: no banner strip —
@@ -12,7 +13,7 @@
   display: flex;
   flex-direction: column;
   width: 100%;
-  max-width: 800px;
+  max-width: var(--dsh-chat-content-width);
   /* Composer seat sits in a fixed-height conversation column (overflow
      hidden): cap the card against the viewport and scroll the option list
      so header and footer actions stay reachable on long batches. */