[Epic] Modernize @atls/nestjs-gateway Apollo runtime

[OsirisAnubiz]

What is this epic about?

Modernize @atls/nestjs-gateway around the current Apollo Server runtime and make the package ready for maintained GraphQL HTTP integrations. The package still depends on apollo-server-express@2.26.2, exposes legacy Apollo types in its public options, hard-codes the Express adapter path, and keeps the gateway integration suite disabled.

Target state

@atls/nestjs-gateway no longer depends on apollo-server-express, uses maintained Apollo Server packages, keeps transport-specific integration code behind explicit adapter boundaries, has a clear path for Express and Fastify support, and validates the gateway through active package-local checks.

Epic definition of done

• apollo-server-express is removed from @atls/nestjs-gateway.
• The Express GraphQL HTTP path works through @apollo/server and a maintained Express integration.
• Fastify support is either implemented through a dedicated adapter boundary or explicitly documented as out of scope for this epic.
• Public gateway options no longer expose legacy Apollo Server 2 types.
• Gateway integration tests are re-enabled or replaced by active package-local coverage.
• GraphQL Mesh and gRPC type suppressions that block the migration are removed or reduced to documented local compatibility boundaries.
• All child issues are closed or explicitly moved out of the epic.