fix: update TypeScript configuration for correct root directory and test exclusion

tsconfig.build.json

@@ -1,10 +1,10 @@
 {
 	"extends": "./tsconfig.json",
 	"compilerOptions": {
-		"rootDir": "./src",
+		"rootDir": "./lib",
 	},
 	"exclude": [
-		"tests/**/*",
+		"*.test.ts",
 		"vitest.config.ts",
 	]
 }