Add four job.workflow_* context properties (fix #647)

[nikolauspschuetz]

Summary

Fixes #647.

The GitHub Actions runner added four new workflow-identity properties to the job context (actions/runner#4335), now documented in the job context reference:

Expression	Description
job.workflow_ref	Full ref of the workflow file
job.workflow_sha	Commit SHA of the resolved workflow file
job.workflow_repository	owner/repo of the workflow file
job.workflow_file_path	.github/workflows/file.yml

Because job is modeled as a strict object type, referencing any of these (e.g. ${{ job.workflow_ref }}) was wrongly reported as:

property "workflow_ref" is not defined in object type {check_run_id: number; container: {...}; services: {...}; status: string} [expression]

This PR adds the four string-typed properties so valid workflows are no longer flagged. This follows the same pattern as the recently-added job.check_run_id property (#576).

Testing

• Added a regression case job.workflow_ref to TestExprSemanticsCheckOK in expr_sema_test.go. It fails on the old code (property reported as undefined) and passes with the fix.
• go test ./... — all packages pass.
• go build ./..., go vet ./..., gofmt -l — all clean.
• Manually confirmed the reproducer (a workflow using all four properties) reports no errors after the fix.

AI assistance

This change was prepared with the help of Claude Code (Anthropic, Opus 4.x). The diff was reviewed and verified locally by the author (build/test/vet/fmt all green; regression test confirmed failing without the fix). The commit carries an Assisted-by: trailer.