fix(deps): upgrade to latest stable — vite 8, vitest 4, vite-plugin-dts 4

Upgrades all build tooling to latest stable versions:
- vite: ^5.4.21 → ^8.0.8 (with rolldown bundler, much faster builds)
- vitest: ^1.5.2 → ^4.1.4 (vitest 4 requires vite 6+)
- vite-plugin-dts: ^3.9.0 → ^4.5.4
- @types/node: ^20.12.7 → ^22.0.0 (vite 8 peer dep requirement)

Migration change in vite.config.ts:
- target: 'modules' → 'es2020' (rolldown no longer accepts the vite-specific
  'modules' shorthand; es2020 is the direct equivalent)

All security CVEs from PR #43 are covered. vitest 4.x itself requires
vite >=6, confirming the full stack upgrade was the right approach.

Supersedes: #43

Author: dtoxvanilla1991

package.json

@@ -23,17 +23,17 @@
   "types": "dist/main.d.ts",
   "devDependencies": {
     "@eslint/js": "^9.4.0",
-    "@types/node": "^20.12.7",
-    "@vitest/coverage-v8": "^1.6.1",
+    "@types/node": "^22.0.0",
+    "@vitest/coverage-v8": "^4.1.4",
     "eslint": "9.x",
     "eslint-plugin-jsdoc": "^50.0.0",
     "globals": "^15.4.0",
     "prettier": "^3.2.5",
     "typescript": "^5.4.5",
     "typescript-eslint": "^7.12.0",
-    "vite": "^5.4.21",
-    "vite-plugin-dts": "^3.9.0",
-    "vitest": "^1.6.1"
+    "vite": "^8.0.8",
+    "vite-plugin-dts": "^4.5.4",
+    "vitest": "^4.1.4"
   },
   "packageManager": "pnpm@8.15.9+sha512.499434c9d8fdd1a2794ebf4552b3b25c0a633abcee5bb15e7b5de90f32f47b513aca98cd5cfd001c31f0db454bc3804edccd578501e4ca293a6816166bbd9f81"
 }