fix: upgrade TypeScript to 5.x for bun-types compatibility

The @types/bun package uses const type parameters which require
TypeScript 5.0+. Also adds skipLibCheck for faster builds.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: v1rtl

bun.lockb

@@ -40,7 +40,7 @@
     "express": "^4.22.1",
     "husky": "^8.0.3",
     "polka": "^1.0.0-next.28",
-    "typescript": "^4.9.5",
+    "typescript": "^5.9.3",
     "ws": "^8.19.0"
   },
   "peerDependencies": {

package.json

@@ -7,7 +7,8 @@
     "rootDir": "src",
     "isolatedModules": true,
     "outDir": "dist",
-    "preserveSymlinks": true
+    "preserveSymlinks": true,
+    "skipLibCheck": true
   },
   "include": ["src/**/*"]
 }