chore(npm): update .npmignore with test-related exclusions

Author: raffaele-filiberti

.npmignore

@@ -2,4 +2,13 @@ demo
 .husky
 .vscode
 .github
-eslint.config.js
+eslint.config.js
+
+# Playwright
+/test-results/
+/playwright-report/
+/blob-report/
+/playwright/.cache/
+
+# Tests
+tests