- Modernize Breadcrumbs: IteratorAggregate, typed params, return types, PHPDoc generics
- Add PHPUnit tests (15 tests), PHPStan at level max, PHP-CS-Fixer config
- Add composer scripts (test, analyse, cs-check, cs-fix)
- Add CLAUDE.md, README with badges, phpstan.neon, phpunit.xml.dist

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>