Backport #312 to old-release: Update README.md

[agent-backport]

Backport: Update README.md to old-release

Summary

This backports a simple documentation update from the main branch that adds ", 4" to the end of "Check 1, 2, 3" text in the README.md file.

Original PR

• Repository: gr2m/sandbox
• Original PR: Update README.md #312 - Update README.md
• Target Branch: old-release
• Change Type: Documentation
• Complexity: Low

Changes

• Extends counting sequence from "Check 1, 2, 3" to "Check 1, 2, 3, 4"
• Documentation-only change with minimal impact

Backport Notes

• ✅ Clean backport with no conflicts expected
• ✅ Aligns with similar changes already present in target branch
• ⚠️ Verify this documentation change is needed for the old-release branch

Testing Recommendations

• Confirm README renders correctly
• Check for any automated tests that might validate specific README text content
• Verify change is consistent with other documentation in the old-release branch

Risk Assessment

Low Risk - Documentation-only change with minimal potential for issues.