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-mission-repository.ts

@@ -0,0 +1,45 @@
+/**
+ * In-Memory Mission Repository
+ *
+ * Adapter: Implements MissionRepository using a Map.
+ * Purpose: Testing, development, CI/CD pipelines.
+ * NOT for production.
+ */
+
+import {
+  Mission,
+  MissionId,
+  SessionId,
+} from '@landvex/domain';
+import { MissionRepository } from '../repositories/repository-interfaces';
+
+export class InMemoryMissionRepository implements MissionRepository {
+  private missions = new Map<string, Mission>();
+
+  async save(mission: Mission): Promise<void> {
+    this.missions.set(mission.id, mission);
+  }
+
+  async findById(id: MissionId): Promise<Mission | null> {
+    return this.missions.get(id) ?? null;
+  }
+
+  async findBySession(sessionId: SessionId): Promise<Mission[]> {
+    return Array.from(this.missions.values())
+      .filter(m => m.sessionId === sessionId)
+      .sort((a, b) => a.sequenceNumber - b.sequenceNumber);
+  }
+
+  async findActive(): Promise<Mission[]> {
+    return Array.from(this.missions.values())
+      .filter(m => m.status === 'created' || m.status === 'uploading' || m.status === 'processing');
+  }
+
+  clear(): void {
+    this.missions.clear();
+  }
+
+  count(): number {
+    return this.missions.size;
+  }
+}