feat(nestjs-gateway): migrate express gateway to apollo server

[TorinAsakura]

Task

• Closes [Dependencies] Update gateway Apollo runtime dependencies #407
• Closes [Feature] Migrate gateway Express integration to @apollo/server #408
• Closes [Feature] Refactor gateway transport architecture #418

How to verify

Main scenario

1. Context: @atls/nestjs-gateway Express gateway runtime after Apollo Server 5 and GraphQL Mesh runtime upgrade
   Action: boot a real Nest HTTP gateway with a gRPC microservice, then execute GraphQL POST requests, GET / with Accept: text/html, and GET /.well-known/apollo/server-health
   Expected result: gateway starts, gRPC query returns data, request metadata reaches gRPC, gRPC errors are exposed as INVALID_ARGUMENT exception data, the Apollo landing page returns HTML 200, and the Apollo health endpoint returns pass

Additional scenario

1. Context: @atls/nestjs-gateway dependency graph after Apollo Server 5 and GraphQL Mesh runtime upgrade
   Action: run package lint, typecheck, focused unit tests, package build, and git whitespace check under the repo-managed Node runtime
   Expected result: validation finishes without errors; existing peer warnings remain warnings

Architecture scenario

1. Context: gateway transport boundaries after Apollo runtime migration
   Action: inspect gateway handler, runtime, and HTTP boundaries
   Expected result: handler selects the Nest HTTP adapter boundary, Express middleware lives only in the Express boundary, Fastify has an explicit boundary, and shared Mesh/Apollo/subscription/gRPC error formatting lives outside the HTTP boundary

Proofs

• package validation

mise x node@22.22.3 -- yarn format packages/nestjs-gateway/src/mesh/graphql-mesh.config.ts packages/nestjs-gateway/src/mesh/graphql-mesh.handler.ts packages/nestjs-gateway/src/mesh/interfaces.ts packages/nestjs-gateway/src/mesh/runtime.ts packages/nestjs-gateway/src/mesh/http/fastify.gateway.ts packages/nestjs-gateway/src/mesh/http/express.gateway.ts
mise x node@22.22.3 -- yarn lint packages/nestjs-gateway
mise x node@22.22.3 -- yarn typecheck packages/nestjs-gateway
mise x node@22.22.3 -- yarn test unit packages/nestjs-gateway/src/mesh/http/tests/express.gateway.test.ts packages/nestjs-gateway/src/mesh/http/tests/fastify.gateway.test.ts packages/nestjs-gateway/src/mesh/tests/config.test.ts
mise x node@22.22.3 -- yarn workspace @atls/nestjs-gateway build
git diff --check HEAD

• unit-runner note

mise x node@22.22.3 -- yarn test unit packages/nestjs-gateway reached 5 pass / 0 fail / 5 files, then did not exit after 90s and was stopped manually. A direct single-file error test is still blocked by the existing Raijin path-duplication bug: ENOENT .../src/mesh/errors/packages/nestjs-gateway/src/mesh/errors/tests/format.test.ts.

• runtime smoke

manual Node smoke from packages/nestjs-gateway with built dist:
gateway-smoke=passed url=http://127.0.0.1:52674 playground=200 health=200

covered:
- Nest HTTP app and gRPC microservice boot
- Movies query returns Mission: Impossible Rogue Nation
- Metadata query forwards Authorization as test
- Error query exposes extensions.exception as INVALID_ARGUMENT / 3 / Test
- GET / with Accept: text/html returns 200 text/html Apollo landing page
- GET /.well-known/apollo/server-health returns 200 application/health+json {"status":"pass"}

• integration-suite note

packages/nestjs-gateway/integration/test/gateway.test.ts is still describe.skip, so the proof above is the real manual boot smoke for this PR. Issue #410 owns restoring the package integration suite.

• compatibility note

The playground option now enables Apollo Server's local landing page plugin. When it is false or absent, the landing page stays disabled. It still drives the default introspection fallback when introspection is not set explicitly.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 97d411c51d

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: f5b142e0fd

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 532d769ebb

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: f1256c0f5e

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 3506ef575a

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".