refactor: centralize action/icon button styles across all tools

Extract shared actionBtn and iconBtn constants into lib/utils/styles.ts
and replace all 11 local definitions across tool components.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/animate/AnimationPreview.tsx

@@ -2,7 +2,7 @@
 
 import { useEffect, useRef, useState } from 'react';
 import { Play, Pause, RotateCcw, Square, Circle, Type } from 'lucide-react';
-import { cn } from '@/lib/utils/cn';
+import { cn, iconBtn } from '@/lib/utils';
 import { buildCSS } from '@/lib/animate/cssBuilder';
 import type { AnimationConfig, PreviewElement } from '@/types/animate';
 
@@ -27,7 +27,7 @@ const ELEMENTS: { value: PreviewElement; icon: React.ReactNode; title: string }[
   { value: 'text', icon: <Type className="w-3 h-3" />, title: 'Text' },
 ];
 
-const actionBtn = 'flex items-center justify-center w-7 h-7 glass rounded-md border border-border/30 text-muted-foreground hover:text-primary hover:border-primary/30 transition-all disabled:opacity-40 disabled:cursor-not-allowed';
+const previewBtn = cn(iconBtn, 'w-7 h-7');
 
 const pillCls = (active: boolean) =>
   cn(
@@ -138,7 +138,7 @@ export function AnimationPreview({ config, element, onElementChange }: Props) {
             onClick={() => animState === 'ended' ? restart() : setAnimState('playing')}
             disabled={animState === 'playing'}
             title={animState === 'ended' ? 'Replay' : 'Play'}
-            className={actionBtn}
+            className={previewBtn}
           >
             <Play className="w-3 h-3" />
           </button>
@@ -146,11 +146,11 @@ export function AnimationPreview({ config, element, onElementChange }: Props) {
             onClick={() => setAnimState('paused')}
             disabled={animState !== 'playing'}
             title="Pause"
-            className={actionBtn}
+            className={previewBtn}
           >
             <Pause className="w-3 h-3" />
           </button>
-          <button onClick={restart} title="Restart" className={actionBtn}>
+          <button onClick={restart} title="Restart" className={previewBtn}>
             <RotateCcw className="w-3 h-3" />
           </button>
         </div>