Add Linux CI build and smoke workflow

[yingyue2030699]

Summary

• Add a Linux GitHub Actions workflow for build and smoke validation.
• Wire CI coverage around the smoke-runner path.

Stack

• Base branch: codex/upgrade-smoke-runner

Validation

• Workflow validation runs in GitHub Actions once opened.

[yingyue2030699]

Mergeability review:

1. Content: Looks aligned with the stated goal. The PR adds .github/workflows/ci.yml with Linux dependency installation, CMake configure/build, smoke-test execution, artifact upload, and optional CTest execution when unit tests are present.
2. Verification: Not verified on the current target branch. GitHub reports no checks for this branch, and the workflow's core build/smoke job would exercise the serial build path. Current master is already build-broken due to duplicate Parameters::bondedComplexWrite declarations, so the merged result cannot be expected to pass this workflow until master is repaired.
3. Dependency: The original stack dependency on codex/upgrade-smoke-runner is complete, but the current target branch build break blocks mergeability.

Decision: Not mergeable right now. The workflow content is directionally complete, but it should wait until master builds cleanly so CI can be validated rather than introduced in a known-failing state.