docs(#242): implementation plan — meta migrate apply-pending

3-task TDD plan: parse the subcommand + config plumbing; runApplyPending
handler + dispatch + d1 rejection + help + tests (incl. real libSQL
provision/idempotent/dry-run/tamper gate); docs + CHANGELOG.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: dmealing