Documents the umbrella-first MVP decision (2026-05-24). This repo remains
INTENT-only until the engine's interfaces stabilize through real product
use. Points at the umbrella's wiki/SharedContracts.md, wiki/DependencyMap.md,
and docs/decisions/ as the canonical homes for cross-repo agreements.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>