Fix path in Xcode selection step of CI workflow

[i-stack]

• Updated the script path in the GitHub Actions workflow to ensure it correctly references the Xcode selection script.
• Adjusted the comment to reflect the correct script location for clarity.

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Note

Low Risk
Low risk CI-only change that updates the Xcode selection step; impact is limited to GitHub Actions build environment and could only fail CI if the runner’s Xcode layout is unexpected.

Overview
Updates the GitHub Actions Swift workflow to call the Xcode selection script from its new location (.github/select_xcode_ci.sh) and fixes the accompanying comment.

Adds a new select_xcode_ci.sh helper that scans /Applications for Xcode_[0-9]*.app/Xcode.app, picks the highest CFBundleShortVersionString, and runs xcode-select so CI builds use the newest installed Xcode.

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