feat(ql3): establish 3.0 incubation baseline

back/runtime/ports/identityDirectoryRepository.ts

@@ -0,0 +1,8 @@
+import type { PolicySubject } from '../domain/projectPolicy';
+
+export interface IdentityDirectoryRepository {
+  resolveAuthenticationSubject(
+    provider: string,
+    providerSubject: string,
+  ): Promise<Readonly<PolicySubject> | null>;
+}