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.rotate.test.tsx

@@ -0,0 +1,57 @@
+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 rotate with snap', () => {
+  it('rotates with 15deg snap by default', () => {
+    const frame = makeFrame()
+    const { getByTestId } = render(<Canvas frame={frame} />)
+    const handle = getByTestId('rotate-handle-o1')
+    const canvas = getByTestId('wysiwyg-canvas')
+
+    // start rotate at 0deg
+    fireEvent.mouseDown(handle, { clientX: 100, clientY: 100 })
+    // move +16px on x → +16deg → snap15 => 15deg
+    fireEvent.mouseMove(canvas, { clientX: 116, clientY: 100 })
+    fireEvent.mouseUp(canvas)
+
+    const obj = getByTestId('obj-o1')
+    expect(obj).toHaveStyle({ transform: 'rotate(15deg)' })
+  })
+
+  it('rotates with 1deg step while holding Shift', () => {
+    const frame = makeFrame()
+    const { getByTestId } = render(<Canvas frame={frame} />)
+    const handle = getByTestId('rotate-handle-o1')
+    const canvas = getByTestId('wysiwyg-canvas')
+
+    fireEvent.mouseDown(handle, { clientX: 100, clientY: 100 })
+    // move +7px with Shift → +7deg, no snap
+    fireEvent.mouseMove(canvas, { clientX: 107, clientY: 100, shiftKey: true })
+    fireEvent.mouseUp(canvas)
+
+    const obj = getByTestId('obj-o1')
+    expect(obj).toHaveStyle({ transform: 'rotate(7deg)' })
+  })
+})