chore(publish): exclude all test files from npm package

Update the files field to properly exclude test files:
- Add `!examples/*.test.ts` to exclude example test files
- Add `!src/**/*.test.ts` to exclude unit test files
- Add `!src/**/*.test-d.ts` to exclude type test files

The previous pattern `!**/*.test.ts` at the start didn't work
because npm applies negation patterns only to already-included files.

Author: ryoppippi

package.json

@@ -28,7 +28,9 @@
 	"module": "./dist/index.mjs",
 	"types": "./dist/index.d.mts",
 	"files": [
-		"!example/*.test.ts",
+		"!examples/*.test.ts",
+		"!src/**/*.test-d.ts",
+		"!src/**/*.test.ts",
 		"LICENSE",
 		"README.md",
 		"dist",