fix: v2.6 组合画布选中根因修复+右键菜单+3D 三场景

- 选中失效根因: Vue3 布尔 prop 缺省转换(editable 缺省→false)
  withDefaults 默认 true 修复, 左键选中/右键选中/菜单动作全链路打通
- 右键菜单: 右键单元弹操作菜单(顺/逆旋转/镜像/底边对齐/删除)
  动作 emit('ctx') 由父组件统一执行, document 级委托
- 3D 三场景: 室内(窗后墙+木地板)/室外(外墙+草地)/影棚(网格)
  场景联动背景色, 真实浏览器截图验证三场景渲染
- 菜单动作行为级验证: 旋转后 1600x1800 宽高互换✓ 删除清空✓

frontend/scripts/verify-menu.mjs

@@ -0,0 +1,41 @@
+// 菜单动作行为级验证: node scripts/verify-menu.mjs <token>
+import puppeteer from 'puppeteer-core'
+const EDGE = 'C:/Program Files (x86)/Microsoft/Edge/Application/msedge.exe'
+const token = process.argv[2]
+const browser = await puppeteer.launch({
+  executablePath: EDGE,
+  headless: 'new',
+  args: ['--window-size=1440,900', '--enable-unsafe-swiftshader', '--use-gl=angle', '--use-angle=swiftshader'],
+  defaultViewport: { width: 1440, height: 900 },
+})
+const page = await browser.newPage()
+await page.goto(`http://localhost:8000/combine?token=${encodeURIComponent(token)}`, { waitUntil: 'networkidle2' })
+await page.waitForSelector('.lib-item')
+await page.click('.lib-item')
+await new Promise(r => setTimeout(r, 600))
+const box = await (await page.$('.canvas-box')).boundingBox()
+const cx = box.x + box.width / 2, cy = box.y + box.height / 2
+
+// ① 右键 → 菜单 → 真实鼠标点击"顺时针旋转90°"
+await page.mouse.click(cx, cy, { button: 'right' })
+await new Promise(r => setTimeout(r, 300))
+const item0 = await page.$$('.ctx-item')
+const r0 = item0.length ? await item0[0].boundingBox() : null
+if (r0) await page.mouse.click(r0.x + r0.width / 2, r0.y + r0.height / 2)
+await new Promise(r => setTimeout(r, 400))
+const hint1 = await page.$eval('.hud span', el => el.textContent)
+console.log('① 旋转后 hint:', hint1, '(原始 1800×1600 → 期望 1600×1800)')
+
+// ② 右键 → 真实鼠标点击"删除单元"
+await page.mouse.click(cx, cy, { button: 'right' })
+await new Promise(r => setTimeout(r, 300))
+const itemN = await page.$$('.ctx-item')
+const rN = itemN.length ? await itemN[itemN.length - 1].boundingBox() : null
+if (rN) await page.mouse.click(rN.x + rN.width / 2, rN.y + rN.height / 2)
+await new Promise(r => setTimeout(r, 400))
+const hint2 = await page.$eval('.hud span', el => el.textContent)
+console.log('② 删除后 hint:', hint2, '(期望"拖入样板开始组合")')
+
+await page.screenshot({ path: 'D:/Code/huamenchuang/shots/v4-menu-actions.png' })
+await browser.close()
+console.log('验证完成')