Per reviewer request (polish only, item 5): added the same "ultimate
source / day-to-day reference" dual-citation to the PRD header's
Terminology alignment line, matching README/TSD/CONTRIBUTING. Named all
three other normative extracts (PhaseManifestSpecification.md,
TargetLedgerSpecification.md, MonetizationExtensionSpecification.md) in
CONTRIBUTING.md's Terminology section, which previously named only
TargetRevenueFrameworkCore.md - now symmetric with README's full
four-document table.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
tegwick
6b34c05e35