RWA category + tokenized equity product pages

[Flotapponnier]

Summary

• New RWA category across the 4 touchpoints (spec-schema zod enum, categories taxonomy + hub copy, category color teal, Benchmark TS union); tokenized-stock-peg moves from Trading to RWA
• 11 equity logos wired (simpleicons SVGs for Apple/Nvidia/Tesla/Palantir/Meta/AMD, Wikimedia for the Google G/Microsoft/State Street, org avatars for Amazon/Micron), aapl + pltr added to the dark mode light chip set
• Registry entries for the 11 tickers: company, token contract address, USDG/Uniswap v4 context, so /products/aapl etc render real descriptions