Add docs/ for newcomers: an index, an architecture deep-dive (the
OBSERVE→DECIDE→ACT loop, the canonical state model, the package layout, every
component, and the load-bearing invariants), and a status/roadmap (what's done
PR-by-PR, what's left, the integration to-dos + carried-forward items, the open
cross-lane contract questions, and where to plug in). Link them from the README.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>