The same icons across the library
The tools directory, tool pages, models, MCP servers, free tools and packs now use the menus' icon set, from the filter bar to the price and fit marks.

Fixes and improvements
- The filters, view buttons and category arrows on the tools page share one line weight
- Price, level, platforms and API on a tool page wear line icons instead of stickers
- The model table's text, image, PDF, audio and video marks match the rest of the site
- The home page's counts and section labels use the same icon as each page in the menu
- Category pictures keep their colour stickers