chore(deps): update dependency eslint to v9 (#11601)

* chore(deps): update dependency eslint to v9

* chore: migrate to eslint flat config files

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Daniel Dietzler <mail@ddietzler.dev>

web/package.json

@@ -23,6 +23,8 @@
     "prepare": "svelte-kit sync"
   },
   "devDependencies": {
+    "@eslint/eslintrc": "^3.1.0",
+    "@eslint/js": "^9.8.0",
     "@faker-js/faker": "^8.4.1",
     "@socket.io/component-emitter": "^3.1.0",
     "@sveltejs/adapter-static": "^3.0.1",
@@ -41,11 +43,12 @@
     "@vitest/coverage-v8": "^2.0.5",
     "autoprefixer": "^10.4.17",
     "dotenv": "^16.4.5",
-    "eslint": "^8.57.0",
+    "eslint": "^9.0.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-svelte": "^2.35.1",
     "eslint-plugin-unicorn": "^55.0.0",
     "factory.ts": "^1.4.1",
+    "globals": "^15.9.0",
     "postcss": "^8.4.35",
     "prettier": "^3.2.5",
     "prettier-plugin-organize-imports": "^4.0.0",