- Track last_login_at on User model, updated on every successful login
- Show last login date in admin panel user table
- Fix admin/garden date display (datetime strings already contain T separator)
- Fix My Garden Internal Server Error (MySQL does not support NULLS LAST syntax)
- Fix Log Batch infinite loop when user has zero varieties
- Auto-fill batch dates from today when creating a new batch, calculated
from selected variety's week offsets (germination, greenhouse, garden)
- Update README with new features and batch date auto-fill formula table
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>