fix(canvas): align workspace headers

src/pages/ImageCanvas/DesignConversationPane.tsx

@@ -4,7 +4,6 @@ import {
   Loader2,
   MessageSquareText,
   Send,
-  Sparkles,
 } from 'lucide-react';
 import { toast } from 'sonner';
 import { Button } from '@/components/ui/button';
@@ -121,16 +120,6 @@ export function DesignConversationPane({
       data-testid="image-workspace-conversation"
       className="flex min-h-0 flex-1 flex-col bg-surface-subtle/45"
     >
-      <header className="border-b border-border/70 bg-background px-5 py-3.5">
-        <div className="flex items-center gap-2">
-          <Sparkles className="h-4 w-4 text-brand" />
-          <h2 className="text-sm font-semibold text-foreground">和 AI 一起完善创作</h2>
-        </div>
-        <p className="mt-1 text-xs leading-5 text-muted-foreground">
-          前面的对话会逐步整理成下方可编辑的创作提示词。
-        </p>
-      </header>
-
       <div className="min-h-0 flex-1 overflow-y-auto px-4 py-5 sm:px-6">
         {workspace.turns.length === 0
           && pendingChatMessages.length === 0 && (

src/pages/ImageCanvas/DesignHistoryRail.tsx

@@ -1,4 +1,4 @@
-import { Clock3, Images } from 'lucide-react';
+import { Images } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import type { DesignWorkspace } from '../../../shared/image-workspace';
 import { DesignPlanHistory } from './DesignPlanHistory';
@@ -14,30 +14,26 @@ export function DesignHistoryRail({ workspace }: { workspace: DesignWorkspace |
       aria-label="历史作品"
       className="flex h-full min-h-0 w-[320px] shrink-0 flex-col border-l border-border/70 bg-background font-sans xl:w-[340px]"
     >
-      <header className={cn(
-        'flex shrink-0 justify-between gap-3 border-b border-border/70 px-4',
-        platform === 'darwin' || platform === 'win32'
-          ? 'min-h-[104px] items-end pb-3 pt-10'
-          : 'min-h-16 items-center',
-      )}>
+      <header
+        data-testid="image-workspace-history-header"
+        className={cn(
+          'flex h-16 shrink-0 items-center border-b border-border/70 px-4',
+          platform === 'darwin' && 'pr-[116px]',
+          platform === 'win32' && 'items-end pb-1.5 pr-[156px]',
+        )}
+      >
         <div className="min-w-0">
           <div className="flex items-center gap-2">
             <Images className="h-4 w-4 shrink-0 text-brand" aria-hidden="true" />
             <h2 className="truncate text-sm font-semibold text-foreground">历史作品</h2>
           </div>
-          <p className="mt-1 text-[11px] tabular-nums text-muted-foreground">
+          <p className={cn(
+            'mt-1 truncate text-[11px] tabular-nums text-muted-foreground',
+            platform === 'win32' && 'hidden',
+          )}>
             {taskCount > 0 ? `${taskCount} 次制作 · ${resultCount} 个结果` : '当前设计项目的制作记录'}
           </p>
         </div>
-        {workspace?.tasks.some((task) => task.status === 'queued' || task.status === 'running') ? (
-          <span
-            role="status"
-            className="inline-flex shrink-0 items-center gap-1.5 rounded-lg bg-brand/[0.06] px-2 py-1 text-[11px] font-medium text-brand"
-          >
-            <Clock3 className="h-3.5 w-3.5 animate-pulse" aria-hidden="true" />
-            制作中
-          </span>
-        ) : null}
       </header>
 
       <div data-testid="image-workspace-history-scroll" className="min-h-0 flex-1 overflow-y-auto overscroll-contain p-3">

src/pages/ImageCanvas/index.tsx

@@ -178,8 +178,8 @@ export function ImageCanvas() {
   return (
     <div data-testid="image-workspace" className="flex h-full min-h-0 overflow-hidden bg-background font-sans">
       <div className="flex min-w-0 flex-1 flex-col">
-        <header className={cn(
-          'flex min-h-16 shrink-0 items-center gap-4 border-b border-border/70 bg-background py-3',
+        <header data-testid="image-workspace-header" className={cn(
+          'flex h-16 shrink-0 items-center gap-4 border-b border-border/70 bg-background py-2',
           platform === 'darwin'
             ? 'pl-4 pr-[116px] sm:pl-5'
             : platform === 'win32'