- Add Optimizer module with lossless WebP conversion
- Generate responsive variants at [400, 800, 1200] widths
- Only create sizes <= source dimensions (no upscaling)
- Support AVIF, WebP, and JPEG output formats
- Add disk cache at priv/static/image_cache/
- Add comprehensive test suite (12 tests)
- Add image fixtures helper for testing
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
