refactor: inject IRepository in PostgresProjector (DIP)

[josecarlospeer-cloud]

Problem

PostgresProjector injected the concrete PostgresRepository class directly:

@inject("infrastructure.transaction.readModel.repository")
private readonly readModel: PostgresRepository  // ← concrete class

Violation: Dependency Inversion Principle — upper layers should depend on abstractions, not concretions. The Domain already defines IRepository; the projector bypassed it.

Source: Evans (Blue Book) — "Interfaces in Domain, implementations in Infrastructure." Martin, Clean Architecture, ch. 11 (DIP).

Consequence: The projector is untestable without a real database. Any change to PostgresRepository's internals could break the projector at a different layer boundary than intended.

Fix

1. Add save(dto: ITransactionReadDTO): Promise<void> to IRepository — uses only primitive types, keeps TypeORM out of the Domain interface.

2. PostgresRepository.save() now maps ITransactionReadDTO → Transactions entity internally. The infrastructure detail stays in Infrastructure.

3. PostgresProjector now depends only on IRepository and builds the DTO inline from the domain event fields.

4. Remove dead Transactions.fromCreated() — was only ever called from the projector; no longer needed.

5. Update InMemoryProjector test double to build the DTO inline (removes its dependency on the deleted factory method).

Tests

All 14 tests pass with no changes to test assertions.