chore: bump TypeScript to v6

The only breaking change that impacts this project is that types are not
imported from `@types` automatically, so we need to specify them in the
root TypeScript config.

Author: rowanmanning

package-lock.json

@@ -38,7 +38,7 @@
     "@types/node": "^24.10.2",
     "husky": "^9.1.7",
     "release-please": "^17.1.3",
-    "typescript": "^5.9.3"
+    "typescript": "^6.0.2"
   },
   "engines": {
     "node": "^22.12 || ^24"

package.json

@@ -22,6 +22,7 @@
 		"strictNullChecks": true,
 		"strictPropertyInitialization": true,
 		"target": "ES2024",
+		"types": ["node"],
 		"useUnknownInCatchVariables": true,
 		"verbatimModuleSyntax": true
 	},