Add 9 built-in classification profile definitions as YAML files bundled
via include_str! for the document type classifier (Phase 5.6).
- Create profiles/builtin/classification/{invoice,receipt,contract,scientific_paper,slide_deck,form,bank_statement,legal_filing,book_chapter}.yaml
- Implement load_builtins() in profiles module with profiles feature gate
- Each profile uses MatchPredicate schema with text patterns, structural signals, page counts
- Add comprehensive unit tests for profile loading and feature gate
Closes: pdftract-5sdd
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
71705ed77b