refactor: rename Hexadeca → unified-api-adapter (estate-wide) (#109)

Estate-wide rename **Hexadeca-Connector → UnifiedApiAdapter**.

- `main-estate-audit.yml`: `uses: …/actions/zig-hexadeca-check@main` →
`…/actions/zig-unified-api-adapter-check@main` (new path live since
cicd-suite#26, expand phase of expand→migrate→contract)
- any residual `hexadeca` prose in-repo renamed with the estate mapping

The old action path is deleted in the contract phase only after code
search shows zero consumers, so this switch cannot break the audit gate.

Co-authored-by: hyperpolymath <hyperpolymath@users.noreply.github.com>

Author: hyperpolymath

.github/workflows/main-estate-audit.yml

@@ -24,8 +24,8 @@ jobs:
       - name: Idris2 ABI Purity Gate
         uses: hyperpolymath/cicd-suite/actions/idris2-abi-check@180b419825d238f8b606584c970a81dfa7cb6f81  # main
 
-      - name: Zig Hexadeca API Gate
-        uses: hyperpolymath/cicd-suite/actions/zig-hexadeca-check@180b419825d238f8b606584c970a81dfa7cb6f81  # main
+      - name: Zig UnifiedApiAdapter API Gate
+        uses: hyperpolymath/cicd-suite/actions/zig-unified-api-adapter-check@180b419825d238f8b606584c970a81dfa7cb6f81  # main
 
       - name: Contractile Validation Gate
         uses: hyperpolymath/cicd-suite/actions/contractile-validation-check@180b419825d238f8b606584c970a81dfa7cb6f81  # main