E2E: 스냅 우선순위 확장 - 센터 우선, 그리드 단독 스냅(13→16) 케이스 추가

tests/e2e/wysiwyg-snap-priority.e2e.ts

@@ -45,4 +45,54 @@ test.describe('WYSIWYG - Snap priority (edge > center > grid)', () => {
     // Allow small tolerance (±1) due to rounding during drag
     expect(Math.abs(s.left - expectedLeft)).toBeLessThanOrEqual(1)
   })
+
+  test('dragging near another object prefers center snap over grid', async ({ page }) => {
+    await page.goto(wysiwygUrl)
+    const canvas = page.getByTestId('wysiwyg-canvas')
+    await expect(canvas).toBeVisible()
+
+    const addText = page.getByRole('button', { name: /^Add Text$/i })
+    await addText.click()
+    await addText.click()
+
+    const first = page.locator('[data-testid^="obj-text-"]').first()
+    const second = page.locator('[data-testid^="obj-text-"]').nth(1)
+    const b1 = await first.boundingBox()
+    const b2 = await second.boundingBox()
+    if (!b1 || !b2) throw new Error('objects not found')
+
+    // Target the center alignment: move second so its centerX ~= first.centerX
+    const firstCenterX = b1.x + b1.width / 2
+    await page.mouse.move(b2.x + b2.width / 2, b2.y + 5)
+    await page.mouse.down()
+    await page.mouse.move(firstCenterX, b2.y + 5)
+    await page.mouse.up()
+
+    const f = await getBox(page, 0)
+    const s = await getBox(page, 1)
+    const sCenter = s.left + Math.round((await second.evaluate((n)=>parseInt((n as HTMLElement).style.width||'0',10))) / 2)
+    expect(Math.abs(sCenter - (f.left + f.width / 2))).toBeLessThanOrEqual(1)
+  })
+
+  test('when no nearby objects, grid snapping applies (13px → 16px)', async ({ page }) => {
+    await page.goto(wysiwygUrl)
+    const canvas = page.getByTestId('wysiwyg-canvas')
+    await expect(canvas).toBeVisible()
+
+    const addText = page.getByRole('button', { name: /^Add Text$/i })
+    await addText.click()
+
+    const obj = page.locator('[data-testid^="obj-text-"]').first()
+    const b = await obj.boundingBox()
+    if (!b) throw new Error('object not found')
+
+    const before = await getBox(page, 0)
+    await page.mouse.move(b.x + 5, b.y + 5)
+    await page.mouse.down()
+    await page.mouse.move(b.x + 5 + 13, b.y + 5)
+    await page.mouse.up()
+
+    const after = await getBox(page, 0)
+    expect(after.left - before.left).toBe(16)
+  })
 })