Add the external Runner foundation with distinct Dot/Grok V6, canonical home-mode V7 and Muse V8 contracts.
Keep generated schemas and profiles synchronized. Bound default question-answer command IDs in a disjoint namespace while preserving existing IDs and durable replay. Preserve canonical migration history and add normally generated, replay-safe Muse schema milestones with literal preview-history fixtures.
Refs #16444.
Co-Authored-By: Paperclip <noreply@paperclip.ing>