tech-design.md §8 settles the stack (Android/Kotlin, Python/FastAPI,
PostgreSQL, WebSocket relay, Room+SQLCipher) so it stops blocking
item 1 of the build order. roadmap.md's Phase 1 breakdown is now
checkboxes instead of prose, and AGENTS.md adds the rule to check/
update that checklist before and after any Phase 1 app-build task,
rather than tracking progress ad hoc.
Introduce a single source of truth for agent guidance during the
planning-docs phase: document authority, tentative Q1-Q7 handling,
v1 scope guards, safety invariants, and next PoC priorities.
Co-authored-by: okuma <o0kuma@users.noreply.github.com>