CI: Update GitHub Actions Go matrix to 1.24–1.26

[Copilot]

This updates the GitHub Actions Go test matrix to cover versions 1.24 through 1.26. The workflow now treats 1.26 as the primary version and keeps 1.25/1.24 as compatibility coverage.

• Go version matrix update

  • Updated .github/workflows/test.yml Go version list from 1.24, 1.23, 1.22 to 1.26, 1.25, 1.24.
  • Preserved existing matrix behavior (go[0] as primary full matrix target, go[1:] for compatibility checks).

• Workflow behavior preserved

  • No changes to OS/MySQL matrix shape, job graph, or test commands.
  • Change is scoped to Go version selection only.

go = [
    '1.26',
    '1.25',
    '1.24',
]

[coveralls]

coverage: 82.496% (-0.1%) from 82.596% — copilot/update-go-version-1-24-to-1-26 into master