Marketplace: Bot detail view with rendered README #919

Parent

#913 · #18

What to build

Opening an entry in the Bot Marketplace modal shows a detail view: the README rendered as sanitized Markdown, with relative image and link URLs rewritten to raw.githubusercontent.com / github.com at the entry's commit so it looks like GitHub, plus stars, last update, tags, a link to the repository and the Install action. The Worker exposes a detail endpoint returning README Markdown and the commit SHA used for rewriting.

Acceptance criteria

• Detail endpoint returns metadata, README Markdown and commit SHA for a listed entry; hidden entries are not served.
• README renders with HTML sanitized (no scripts, event handlers or unsafe URLs).
• Relative images and links resolve against the entry's commit on GitHub.
• Detail view links to the repository and offers Install with the existing confirmation.
• Tests cover sanitization of hostile Markdown/HTML and URL rewriting; Client tests cover the view against a mocked bridge.

Blocked by

• Tracer: paste a GitHub repo, see it in the Marketplace modal, install it #916