SKILL.md now renders via MailboxMessageContent (markdown + sanitized HTML + mermaid) instead of raw <pre>. Files strip is compact and lists all files; clicking a file loads its content in the detail pane (markdown via MailboxMessageContent, other text via <pre>, binary/oversized notice) with a Back-to-SKILL.md affordance. New GET /api/skills/:id/file endpoint (readSkillFileContent: path-traversal-guarded, 2MB ceiling, binary detection) + fetchSkillFileContent client fn.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>