visual testing

frontend/package.json

@@ -9,7 +9,8 @@
     "preview": "vite preview",
     "test": "vitest",
     "test:run": "vitest run",
-    "test:visual": "playwright test"
+    "test:visual": "playwright test",
+    "test:visual:cross": "playwright test --project=cross-renderer"
   },
   "dependencies": {
     "@codemirror/autocomplete": "^6.20.1",
@@ -26,10 +27,13 @@
   "devDependencies": {
     "@playwright/test": "^1.58.2",
     "@types/node": "^25.5.0",
+    "@types/pngjs": "^6.0.5",
     "@vitejs/plugin-vue": "^6.0.5",
     "@vue/test-utils": "^2.4.6",
     "@vue/tsconfig": "^0.9.0",
     "happy-dom": "^20.8.9",
+    "pixelmatch": "^7.1.0",
+    "pngjs": "^7.0.0",
     "typescript": "~6.0.2",
     "vite": "^8.0.1",
     "vitest": "^4.1.2",