docs: add ADR 011 — agent command surface (lazy-mcp pattern)

Documents the design decision for the Orbit agent command surface, as discussed in the GKG Tool Design Sync on 2026-05-06.

Note

Click here for rendered version

Relates to:

• gitlab-org/gitlab!234925 (merged)
• gitlab-org/modelops/applied-ml/code-suggestions/ai-assist!5446 (merged)
• !1252 (merged)