PR-002: Persistence Adapters — in-memory, zero external dependencies

- Repository interfaces defined by domain (@landvex/domain)
- 6 in-memory adapters: Session, Mission, DecisionCase, Artifact, EventStore, UnitOfWork
- 9 tests verifying adapter contracts
- Domain unchanged — infrastructure depends on domain, never reverse
- ADR-006: In-Memory Adapters for Testing

Definition of Done met:
- All adapters compile against domain interfaces
- Unit tests pass (9/9)
- No PostgreSQL, S3, Express, AI in this PR
- Ready for PR-003: PostgreSQL adapters

packages/infrastructure/src/index.ts

@@ -0,0 +1,29 @@
+/**
+ * @landvex/infrastructure
+ *
+ * Persistence adapters and infrastructure for LandveX domain.
+ *
+ * Architecture:
+ * - Domain defines interfaces (WHAT)
+ * - Infrastructure implements them (HOW)
+ * - Domain never depends on infrastructure
+ */
+
+// Repository interfaces (defined by domain, exported for convenience)
+export {
+  Repository,
+  FieldSessionRepository,
+  MissionRepository,
+  DecisionCaseRepository,
+  ArtifactRegistry,
+  EventStore,
+  UnitOfWork,
+} from './repositories/repository-interfaces';
+
+// In-memory adapters (for testing)
+export { InMemoryFieldSessionRepository } from './adapters/in-memory-session-repository';
+export { InMemoryMissionRepository } from './adapters/in-memory-mission-repository';
+export { InMemoryDecisionCaseRepository } from './adapters/in-memory-decision-case-repository';
+export { InMemoryArtifactRegistry } from './adapters/in-memory-artifact-registry';
+export { InMemoryEventStore } from './adapters/in-memory-event-store';
+export { InMemoryUnitOfWork } from './adapters/in-memory-unit-of-work';