refactor: convert mock repositories to singletons for consistent data sharing

Co-authored-by: aider (anthropic/claude-sonnet-4-20250514) <[e-mail]>

src/modules/cards/tests/utils/InMemoryCardRepository.ts

···
 import { URL } from '../../domain/value-objects/URL';
 
 export class InMemoryCardRepository implements ICardRepository {
+  private static instance: InMemoryCardRepository;
   private cards: Map<string, Card> = new Map();
   private shouldFail: boolean = false;
   private shouldFailSave: boolean = false;
+
+  private constructor() {}
+
+  public static getInstance(): InMemoryCardRepository {
+    if (!InMemoryCardRepository.instance) {
+      InMemoryCardRepository.instance = new InMemoryCardRepository();
+    }
+    return InMemoryCardRepository.instance;
+  }
 
   private clone(card: Card): Card {
     // Simple clone - in a real implementation you'd want proper deep cloning

src/modules/cards/tests/utils/InMemoryCollectionRepository.ts

···
 import { CuratorId } from '../../domain/value-objects/CuratorId';
 
 export class InMemoryCollectionRepository implements ICollectionRepository {
+  private static instance: InMemoryCollectionRepository;
   private collections: Map<string, Collection> = new Map();
+
+  private constructor() {}
+
+  public static getInstance(): InMemoryCollectionRepository {
+    if (!InMemoryCollectionRepository.instance) {
+      InMemoryCollectionRepository.instance = new InMemoryCollectionRepository();
+    }
+    return InMemoryCollectionRepository.instance;
+  }
 
   private clone(collection: Collection): Collection {
     // Simple clone - in a real implementation you'd want proper deep cloning

src/modules/user/tests/infrastructure/InMemoryUserRepository.ts

···
 import { DID } from '../../domain/value-objects/DID';
 
 export class InMemoryUserRepository implements IUserRepository {
+  private static instance: InMemoryUserRepository;
   private users: Map<string, User> = new Map();
+
+  private constructor() {}
+
+  public static getInstance(): InMemoryUserRepository {
+    if (!InMemoryUserRepository.instance) {
+      InMemoryUserRepository.instance = new InMemoryUserRepository();
+    }
+    return InMemoryUserRepository.instance;
+  }
 
   async findByDID(did: DID): Promise<Result<User | null>> {
     try {

src/shared/infrastructure/http/factories/RepositoryFactory.ts

···
     const useMockRepos = process.env.USE_MOCK_REPOS === 'true';
 
     if (useMockRepos) {
-      // Create in-memory repositories
-      const userRepository = new InMemoryUserRepository();
-      const tokenRepository = new InMemoryTokenRepository();
-      const cardRepository = new InMemoryCardRepository();
-      const collectionRepository = new InMemoryCollectionRepository();
+      // Use singleton instances to ensure same data across processes
+      const userRepository = InMemoryUserRepository.getInstance();
+      const tokenRepository = InMemoryTokenRepository.getInstance();
+      const cardRepository = InMemoryCardRepository.getInstance();
+      const collectionRepository = InMemoryCollectionRepository.getInstance();
       const cardQueryRepository = new InMemoryCardQueryRepository(
         cardRepository,
         collectionRepository,
···
         cardRepository,
       );
       const appPasswordSessionRepository =
-        new InMemoryAppPasswordSessionRepository();
+        InMemoryAppPasswordSessionRepository.getInstance();
       const feedRepository = InMemoryFeedRepository.getInstance();
       const atUriResolutionService = new InMemoryAtUriResolutionService(
         collectionRepository,
       );
-      const oauthStateStore = new InMemoryStateStore();
-      const oauthSessionStore = new InMemorySessionStore();
+      const oauthStateStore = InMemoryStateStore.getInstance();
+      const oauthSessionStore = InMemorySessionStore.getInstance();
 
       return {
         userRepository,