[aheritier]

On Linux CI, set GOMAXPROCS=1 only for race tests of the TypeScript generator package as a temporary mitigation for golang/go#81122. Race checks remain enabled for every package. This is not an upstream fix; track the issue separately: #4804, #4805, #4806, #4807, #4810, #4873, #4874, #4890.

Validation:

• Linux/arm64 Alpine full race suite passed: 322 distinct packages in 264 seconds.
• task build and task test passed.
• task lint failed on three errcheck findings in untouched files using local golangci-lint 2.15.0 (CI uses 2.14.0).
• Hosted Linux/amd64 CI is unverified.

[Copilot]

🟢 Approval recommended

There are no active review issues blocking the CI race-test mitigation.

No open issues 🎉

What changed in this PR

Temporarily mitigates the TypeScript generator’s Linux CI race-test failures associated with golang/go#81122. The change isolates that package with GOMAXPROCS=1 while keeping race detection enabled for every package; it does not fix the upstream issue.

Changes:

• Splits CI race testing into ordinary packages and a separate generator run, validating package discovery first.
• Adds a dedicated CI task without changing the existing test-race task.
• Adds mocked shell regression tests for package selection, environment isolation, and failure handling, and runs them in CI.

File	Description
Taskfile.yml	Adds the test-race-ci task using the test environment.
scripts/​test-race-ci.sh	Separates race-test runs and limits only the generator to GOMAXPROCS=1.
scripts/​test-race-ci-test.sh	Tests package discovery, command arguments, environment isolation, and failures.
.github/​workflows/​ci.yml	Runs the shell regression tests and switches the race job to the dedicated CI task.

_{Review effort: Balanced}