- Replace multiple consecutive spaces with single underscore for tag matching
(e.g., 'looking to the side' → 'looking_to_the_side')
- Support prefix/suffix matching for flexible multi-word autocomplete
(e.g., 'looking to the' → 'looking_to_the_side')
- Add comprehensive test coverage for multi-word scenarios
Test coverage:
- Multi-word exact match (Danbooru convention)
- Partial match with last token replacement
- Command mode with multi-word phrases
- Multiple consecutive spaces handling
- Backend LOG10 popularity weight validation
Fixes: 'looking to the side' input now correctly replaces with
'looking_to_the_side, ' (or 'looking to the side, ' with space replacement)