New doc (docs/architecture/workspace-concurrency.md) explains:
- why lockMode='none' is the default (cognitive tasks run in
parallel with no lock)
- what tasks.requires_filesystem means and how v52 backfills it
- the coding-role inference safety net during the v52 transition
- the per-task decision table the resolver implements
- why company_fallback was removed and what replaces it
- the type-enforced invariants on the resolution pair
- failure modes and how heartbeat/task-runner recover
Also adds /docs/architecture/*.md to the .gitignore allowlist so the
docs directory is tracked the same way /docs/*.md and
/docs/proposals/*.md already are.
ZacharyZhang-NY
c3dd08ec65