Add a grounded doc set under docs/ plus a root CONTRIBUTING.md:
- docs/ARCHITECTURE.md: current code shape (layers, data seam, provider
resolution, reminder engine, DI, build/tooling, manifest)
- docs/ROADMAP.md: status view (M0/M1 done, M2 in progress, open decisions)
- docs/RELEASING.md: tag-driven release flow, CI jobs, F-Droid repo, secrets
(was referenced by build.gradle.kts and CHANGELOG but missing)
- docs/README.md: docs index and how the docs relate
- CONTRIBUTING.md: build/test/lint, layer rules, style, PR conventions
Also refresh the stale "M0 — skeleton" status note in README.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>