chore: upgrade tooling stack

- TypeScript 3.9 -> 5.8
- ESLint 6 -> 9 (flat config)
- Prettier 1 -> 3
- eslint-plugin-vue 6 -> 9
- Add vue-tsc for type checking
- Migrate Sass @import to @use syntax
- Fix Pinia persistence config for v4
- Add Spotify type declarations
- Remove unused registerServiceWorker.ts

package.json

@@ -7,7 +7,8 @@
     "dev": "vite",
     "build": "vite build",
     "preview": "vite preview",
-    "lint": "eslint src --ext .vue,.js,.jsx,.cjs,.mjs,.ts,.tsx,.cts,.mts --fix --ignore-path .gitignore"
+    "type-check": "vue-tsc --noEmit",
+    "lint": "eslint src --fix"
   },
   "dependencies": {
     "core-js": "^3.6.5",
@@ -20,21 +21,21 @@
     "vue-router": "^4.5.1"
   },
   "devDependencies": {
+    "@eslint/js": "^9.39.2",
     "@intlify/unplugin-vue-i18n": "^6.0.8",
-    "@types/webpack": "^4.4.0",
-    "@typescript-eslint/eslint-plugin": "^2.33.0",
-    "@typescript-eslint/parser": "^2.33.0",
+    "@types/node": "^25.0.10",
     "@vitejs/plugin-legacy": "^7.0.1",
     "@vitejs/plugin-vue": "^6.0.0",
-    "eslint": "^6.7.2",
-    "eslint-plugin-prettier": "^3.1.3",
-    "eslint-plugin-vue": "^6.2.2",
-    "prettier": "^1.19.1",
+    "eslint": "^9.18.0",
+    "eslint-config-prettier": "^10.0.1",
+    "eslint-plugin-vue": "^9.32.0",
+    "prettier": "^3.4.2",
     "sass": "^1.89.2",
-    "sass-loader": "^8.0.2",
-    "typescript": "~3.9.3",
+    "typescript": "^5.8.0",
+    "typescript-eslint": "^8.21.0",
     "vite": "^7.0.5",
     "vite-plugin-pwa": "^1.0.1",
+    "vue-tsc": "^2.2.0",
     "workbox-build": "^7.3.0",
     "workbox-window": "^7.3.0"
   }