- Handle llm.pricing_display when it's a string (not array)
- Card cwidth 15→25 to fill DynamicColumn properly
- Added page/page_size pagination with prev/next buttons
- page param forwarded through model_plaza→plaza_model_cards
New layout:
- Search bar (top) with fuzzy name/description match
- Category tabs (wrapping, single-select)
- Provider sidebar (left, single-select)
- Card grid (right, sorted by name, refreshed on filter change)
- Both category/provider unselected = all published models
Added get_plaza_models() for flat filtered model listing.
Supports combined filtering: provider + category + search.
