Remove Cypress and update scripts to use Playwright for E2E testing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -9,10 +9,9 @@
     "preview": "vite preview",
     "test": "vitest",
     "coverage": "vitest run --coverage",
-    "cy:run": "cypress run",
-    "test:unit": "vitest --environment jsdom",
-    "test:e2e": "start-server-and-test 'vite preview --port 4173' :4173 'cypress run --e2e'",
-    "test:e2e:dev": "start-server-and-test 'vite dev --port 4173' :4173 'cypress open --e2e'",
+    "test:unit": "vitest run",
+    "test:e2e": "playwright test --config tests/e2e/playwright.config.ts",
+    "test:e2e:ui": "playwright test --config tests/e2e/playwright.config.ts --ui",
     "lint": "eslint . --ext .vue,.js,.jsx,.cjs,.mjs",
     "lint:fix": "eslint . --ext .vue,.js,.jsx,.cjs,.mjs --fix",
     "docs": "typedoc"
@@ -49,7 +48,6 @@
     "vuedraggable": "^4.1.0"
   },
   "devDependencies": {
-    "@4tw/cypress-drag-drop": "^2.3.1",
     "@eslint/js": "^10.0.1",
     "@playwright/test": "^1.58.2",
     "@types/cytoscape": "^3.21.9",
@@ -60,17 +58,13 @@
     "@vue/eslint-config-prettier": "^10.2.0",
     "@vue/test-utils": "^2.4.6",
     "chartjs-plugin-dragdata": "^2.3.1",
-    "cypress": "^15.11.0",
-    "cypress-xpath": "^2.0.1",
     "eslint": "^10.0.2",
-    "eslint-plugin-cypress": "^6.1.0",
     "eslint-plugin-vue": "^10.8.0",
     "jsdom": "^28.1.0",
     "msw": "^2.12.14",
     "postcss": "^8.5.8",
     "prettier": "^3.8.1",
     "sass": "^1.97.3",
-    "start-server-and-test": "^2.1.5",
     "tailwindcss": "^4.2.1",
     "ts-node": "^10.9.2",
     "typedoc": "^0.28.17",