feat(wysiwyg): 레이어/속성 패널 및 Export(절대배치) 1차 TDD/구현

- LayersPanel: 순서 변경/잠금/숨김 토글
- PropsPanel: 위치/크기/회전 및 이미지 src/alt 편집
- exportFrame: frame-scale 토큰 및 오브젝트 절대배치 HTML/CSS 출력
- 테스트 추가 및 전체 그린 유지

components/wysiwyg/Canvas.resize.test.tsx

@@ -0,0 +1,42 @@
+import { describe, it, expect } from 'vitest'
+import { render, fireEvent } from '@testing-library/react'
+import { Canvas } from '@/components/wysiwyg/Canvas'
+import type { Frame } from '@/lib/wysiwyg/schema'
+
+function makeFrame(): Frame {
+  return {
+    id: 'f1',
+    width: 400,
+    height: 300,
+    background: '#ffffff',
+    layers: [
+      {
+        id: 'l1',
+        name: 'L1',
+        visible: true,
+        locked: false,
+        objects: [
+          { id: 'o1', type: 'image', x: 100, y: 100, width: 50, height: 40, rotate: 0, zIndex: 0, props: { src: 'x', alt: '' } },
+        ],
+      },
+    ],
+  }
+}
+
+describe('WYSIWYG Canvas resize with 8px snap', () => {
+  it('dragging bottom-right handle resizes and snaps to nearest 8px', () => {
+    const frame = makeFrame()
+    const { getByTestId } = render(<Canvas frame={frame} />)
+    const handle = getByTestId('resize-handle-o1')
+    const canvas = getByTestId('wysiwyg-canvas')
+
+    // start resize
+    fireEvent.mouseDown(handle, { clientX: 150, clientY: 140 })
+    // move by +7,+9 → width 50-> 57 -> snap8 => 56, height 40->49 -> snap8 => 48
+    fireEvent.mouseMove(canvas, { clientX: 157, clientY: 149 })
+    fireEvent.mouseUp(canvas)
+
+    const obj = getByTestId('obj-o1')
+    expect(obj).toHaveStyle({ width: '56px', height: '48px' })
+  })
+})