Three solanabr repos publish a marketplace named stbr #88

Problem

Claude Code registers one marketplace per name per user. Three SuperteamBR repos all call their marketplace stbr:

The kit's .claude/settings.json declares extraKnownMarketplaces.stbr pointing at solanabr/ai-kit and enables safe-ai-skill@stbr. A user who followed the safe-ai-skill or writer-style-skill README already has stbr pointing at another repo. Then:

• solana-ai-kit@stbr doesn't resolve, or
• adding the kit's marketplace replaces theirs.

Upstream report: solanabr/safe-ai-skill#8.

Options

1. Make solanabr/ai-kit the one stbr marketplace and list every SuperteamBR plugin in it, as it already does for safe-ai-skill. Rename the other two repos' marketplaces (e.g. safe-ai-skill, writer-style-skill) or remove their marketplace.json.
2. Rename this kit's marketplace. This changes the install command for every existing user, so it's the less attractive option.

Acceptance

• Each marketplace name is used by only one solanabr repo.
• README install steps for each repo work when run in either order.