Replace the structured search filter approach with from_text(), enabling
the full search syntax (is:nc, occupies:background, user:owns, etc.) in
a single text field.
Changes:
- Search form now uses single `q` text param instead of `q[name]`
- Controller uses Item::Search::Query.from_text instead of from_params
- Auto-fit filter applied via .merge(Item.fits(body_id)) in controller
- Added error handling for Item::Search::Error
- Updated pagination param from `q[page]` to `page`
- Removed build_search_filters method (no longer needed)
- Fixed outfit_state_params helper to handle q as string
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
