Bump actions/checkout from 2 to 7 - #12

Overall Assessment

This PR updates actions/checkout from v2 to v7 in three GitHub Actions workflow files. The changes are direct version bumps with no modifications to workflow logic, triggers, or step usage. No blocking bugs found.

Findings

No actionable findings.

Notes

• The workflows use push, pull_request, schedule, workflow_dispatch, and repository_dispatch triggers; none of the v7 changes around pull_request_target/workflow_run fork checkout blocking apply here.
• Considered verifying the v7 tag existence online per review guidelines but release notes in the PR description already confirm v7.0.0 availability and changes.
• No other files outside the diff were needed for context since the YAMLs are self-contained.