BL-073 Shipped

Sentinel agent definition

updated .claude/agents/sentinel.md with the campaign audit mode: the four checks (unresolved links, orphans, privacy leaks, stale articles), auto-fix workflow, MCP tools table, and guidance for when the Archivist should delegate here. Description frontmatter updated. The Archivist can now spawn the Sentinel as a subagent for wiki audit work mid-conversation.