feat(skill): /whois — evidence-backed expertise map

[norrietaylor]

Summary

Add a /whois skill that maps team members to their areas of expertise based on their knowledge base contributions.

Behavior

/whois auth            # Who knows about authentication?
/whois                 # Show full team expertise map
/whois --user alice    # What does Alice know about?

Implementation

Uses NetworkX (#138) to build an author→tag→entry graph:

• nx.degree_centrality() ranks expertise areas per author
• Tag co-occurrence reveals topic clusters each person covers
• Entry recency weights recent contributions higher

Output

## Expertise Map: authentication

| Author | Expertise Score | Key Entries | Last Active |
|--------|----------------|-------------|-------------|
| Norrie Taylor | 0.85 | OAuth middleware, org restriction, auth audit | 2026-04-05 |

Related expertise: deployment, middleware, security

Dependencies

• Use NetworkX for graph analysis in team skills (/whois, /investigate) #138 — NetworkX infrastructure
• feat(auth): GitHub-backed access control for entry visibility #149 — Access control (respect visibility in expertise queries)

References

• Roadmap: planned skill
• Team access prioritization: Sprint 4