docs(data): ADR-0002 + per-directory READMEs — populate, not remove (#5) (#22)

The dispatch/patterns/recipes/outcomes/policy/health/.well-known dirs
flagged as "empty placeholders" are now live data sinks for the
scan→triage→autofix pipeline. Records the populate-not-remove decision
in ADR-0002 and adds the missing per-directory README explaining
contents, format, writer/reader, and append-vs-rewrite semantics for
each. No data files moved or removed; outcomes/.gitkeep documented as
intentional. Closes #5.

Co-authored-by: hyperpolymath <hyperpolymath@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: hyperpolymath