Introduces the ExtensionData namespace with the full contract and service
layer that future extension records (municipality profiles, election jobs,
service configs) will use to store and validate their legacy foreign references.
- LegacyLinkType enum (JurisdictionJCode, KitId, ContactId)
- LegacyLinkReference value record with typed factory methods
- ILegacyLinkValidator / LegacyLinkValidator — validates each link type
against the anti-corruption layer; returns descriptive errors on failure
- ILegacyLinkedRecord / ILegacyLinkedRecordProvider — contracts extension
record types implement to participate in integrity checks
- ILegacyLinkIntegrityCheck / LegacyLinkIntegrityService — scans all
registered providers, computes consistency percentage (NFR13 target 99.9%)
- POST /api/admin/legacy-link/integrity-check (Admin-only, audit-logged)
- 19 unit tests covering all four ACs
Stories 1.10-1.13 register ILegacyLinkedRecordProvider implementations.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Daniel Covington