Upgrade ESLint from 8 to 9 with flat config migration

Replace .eslintrc.cjs with eslint.config.mjs, upgrade eslint-plugin-vue
to 10, eslint-plugin-cypress to 6, @vue/eslint-config-prettier to 10,
and remove @rushstack/eslint-patch.

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

package.json

@@ -48,20 +48,19 @@
   },
   "devDependencies": {
     "@4tw/cypress-drag-drop": "^2.3.1",
-    "@rushstack/eslint-patch": "^1.16.1",
     "@types/cytoscape": "^3.21.9",
     "@types/cytoscape-dagre": "^2.3.4",
     "@types/cytoscape-popper": "^2.0.4",
     "@types/node": "^20.19.37",
     "@vitejs/plugin-vue": "^5.2.4",
-    "@vue/eslint-config-prettier": "^7.0.0",
+    "@vue/eslint-config-prettier": "^10.2.0",
     "@vue/test-utils": "^2.4.6",
     "autoprefixer": "^10.4.27",
     "cypress": "^15.11.0",
     "cypress-xpath": "^2.0.1",
-    "eslint": "^8.22.0",
-    "eslint-plugin-cypress": "^2.15.2",
-    "eslint-plugin-vue": "^9.33.0",
+    "eslint": "^9.39.3",
+    "eslint-plugin-cypress": "^6.1.0",
+    "eslint-plugin-vue": "^10.8.0",
     "jsdom": "^28.1.0",
     "postcss": "^8.5.8",
     "prettier": "^3.8.1",
@@ -71,6 +70,7 @@
     "ts-node": "^10.9.2",
     "typescript": "^5.9.3",
     "vite": "^6.4.1",
-    "vitest": "^3.2.4"
+    "vitest": "^3.2.4",
+    "vue-eslint-parser": "^10.4.0"
   }
 }