chore(deps): add Laravel Boost development tooling and configuration

Add laravel/boost as a dev dependency, enable MCP server and skills via boost.json, and include AGENTS.md guidelines. Update .gitignore to exclude .env.testing, /.kilo, and /.cursor.

.gitignore

@@ -11,6 +11,7 @@
 .env
 .env.backup
 .env.production
+.env.testing
 .phpunit.result.cache
 Homestead.json
 Homestead.yaml
@@ -21,3 +22,5 @@ yarn-error.log
 /.idea
 /.vscode
 .directory
+/.kilo
+/.cursor