feat: M5 背景图上传/压缩+智能取色（FR-A8/A9，smart-color 下沉 shared，canvas 采样→analyzeImage 推导强调色/模糊/表面不透明尊重手动项，持久化+重开恢复）

apps/desktop/src/renderer/App.tsx

@@ -43,7 +43,9 @@ export function App() {
   // 编辑器样式随设置生效（FR-编辑器设置真实生效）
   useEffect(() => { document.documentElement.style.setProperty('--editor-font-size', settings.fontSize + 'px'); document.documentElement.style.setProperty('--editor-font-family', settings.fontFamily); document.documentElement.style.setProperty('--editor-white-space', settings.wordWrap ? 'pre-wrap' : 'pre'); }, [settings.fontSize, settings.fontFamily, settings.wordWrap]);
   return (
-    <div style={{ display: 'flex', flexDirection: 'column', height: '100vh', background: 'var(--bg-primary, #1a1a1a)', color: '#ddd' }}>
+    <div style={{ position: 'relative', display: 'flex', flexDirection: 'column', height: '100vh', background: 'var(--bg-primary, #1a1a1a)', color: '#ddd' }}>
+      {appearance.bgImage && <div style={{ position: 'absolute', inset: 0, backgroundImage: 'url(' + appearance.bgImage + ')', backgroundSize: 'cover', backgroundPosition: 'center', filter: 'blur(var(--blur-px,0px))', opacity: 0.45, zIndex: 0, pointerEvents: 'none' }} />}
+      <div style={{ position: 'relative', zIndex: 1, display: 'flex', flexDirection: 'column', height: '100vh' }}>
       <TitleBar view={view} onToggleView={() => setView(v => v === 'editor' ? 'graph' : 'editor')} onSettings={() => setShowSettings(true)} onAppearance={() => setShowAppearance(true)} onToggleSidebar={() => layout.toggleSidebar()} onToggleMinimal={() => layout.toggleMinimal()} minimal={layout.minimal} />
       <Toolbar />
       {view === 'editor' && <TabBar />}
@@ -76,6 +78,7 @@ export function App() {
       {showSettings && <SettingsPanel onClose={() => setShowSettings(false)} />}
       {showAppearance && <AppearancePanel onClose={() => setShowAppearance(false)} />}
       {showCheat && <CheatSheet onClose={() => setShowCheat(false)} />}
+      </div>
     </div>
   );
 }