refactor(config): motion polish and reduced-motion coverage pass

src/components/ui/Collapsible/Collapsible.module.scss

@@ -53,7 +53,7 @@
   width: 16px;
   height: 16px;
   color: var(--muted-foreground);
-  transition: transform 200ms ease;
+  transition: transform var(--dur-hover, 200ms) var(--ease-out-strong, ease-out);
   flex-shrink: 0;
 
   .root[open] & {
@@ -70,3 +70,27 @@
   padding: 0;
   border-top: 1px solid var(--border-color);
 }
+
+/* 展开时内容 160ms 淡入。只做透明度、不做高度动画 ——
+   与程序化 details.open = true（搜索跳转强制展开）不会互相打架。 */
+.root[open] > .content,
+.root[open] > .contentFlush {
+  animation: collapsible-content-in var(--dur-press, 160ms) var(--ease-out-strong, ease-out);
+}
+
+@keyframes collapsible-content-in {
+  from {
+    opacity: 0;
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .chevron {
+    transition: none;
+  }
+
+  .root[open] > .content,
+  .root[open] > .contentFlush {
+    animation: none;
+  }
+}

src/features/config/components/DiffModal.module.scss

@@ -1,7 +1,7 @@
 @use '../../../styles/variables' as *;
 @use '../../../styles/mixins' as *;
 
-$diff-mono: 'Consolas', 'Monaco', 'Menlo', 'SF Mono', monospace;
+$diff-mono: $font-mono;
 $diff-font-size: 12px;
 $diff-line-height: 20px;
 $diff-gutter-width: 50px;

src/features/config/components/SectionCard.module.scss

@@ -19,9 +19,10 @@
   }
 }
 
-/* 首载入场：0.45s 强减速上浮（与全站卡片入场同拍），仅挂载时播一次 */
+/* 首载入场：0.45s 强减速上浮（与全站卡片入场同拍），排在头部级联
+   （标题 0 / meta 70 / 动作 140 / 工具栏 210 / tabs 280ms）之后收尾，仅首载播一次 */
 .cardEnter {
-  animation: config-card-in 0.45s var(--ease-out-strong, ease-out) 0.28s backwards;
+  animation: config-card-in 0.45s var(--ease-out-strong, ease-out) 0.32s backwards;
 }
 
 @keyframes config-card-in {