chore(Item 11): drop duplicate .md docs (RSR-canonical .adoc retained) (#43)

Day 10 / Item 11 (estate `.md`->`.adoc` dedupe). Removes duplicate doc
files
where the `.adoc` counterpart was verified a faithful superset (0
`.md`-only
content tokens; vocabulary coverage >=93%). The `.adoc` is the
RSR-canonical
format. Inbound links that resolved to the removed file(s) are repointed
to
`.adoc`. No content lost. Audit basis: Estate Debt Recovery Day 10.

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

Author: hyperpolymath