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/adapters/in-memory-event-store.ts

@@ -0,0 +1,45 @@
+/**
+ * In-Memory Event Store
+ *
+ * Adapter: Implements EventStore using an array.
+ * Purpose: Testing, development, CI/CD pipelines.
+ * NOT for production.
+ *
+ * ADR-003: Event Sourcing for traceability
+ * - Events are immutable facts
+ * - State is a projection of event history
+ * - Replay reconstructs any past state
+ */
+
+import { DomainEvent } from '@landvex/domain';
+import { EventStore } from '../repositories/repository-interfaces';
+
+export class InMemoryEventStore implements EventStore {
+  private events: DomainEvent[] = [];
+
+  async append(event: DomainEvent): Promise<void> {
+    this.events.push(event);
+  }
+
+  async getEvents(aggregateId: string): Promise<DomainEvent[]> {
+    return this.events
+      .filter(e => e.aggregateId === aggregateId)
+      .sort((a, b) => a.occurredAt.getTime() - b.occurredAt.getTime());
+  }
+
+  async getAllEvents(since?: Date): Promise<DomainEvent[]> {
+    let filtered = this.events;
+    if (since) {
+      filtered = filtered.filter(e => e.occurredAt >= since);
+    }
+    return filtered.sort((a, b) => a.occurredAt.getTime() - b.occurredAt.getTime());
+  }
+
+  clear(): void {
+    this.events = [];
+  }
+
+  count(): number {
+    return this.events.length;
+  }
+}