feat(infrastructure): ProductTypeRepository Dapper + DI wiring (PRD-001)

CRUD + paginado con filtros sobre dbo.ProductType; history temporal verificada en tests.
11 integration tests nuevos, suite total 935 GREEN.

src/api/SIGCM2.Infrastructure/DependencyInjection.cs

@@ -39,6 +39,7 @@ public static class DependencyInjection
         services.AddScoped<ITipoDeIvaRepository, TipoDeIvaRepository>();
         services.AddScoped<IIngresosBrutosRepository, IngresosBrutosRepository>();
         services.AddScoped<IRubroRepository, RubroRepository>();
+        services.AddScoped<IProductTypeRepository, ProductTypeRepository>();
 
         // JWT Options — bound lazily via IOptions so tests can override via ConfigureWebHost
         services.Configure<JwtOptions>(configuration.GetSection("Jwt"));