Codex suggestion: Evaluate Xcode entitlement settings migration

[pascalpp]

Summary

Evaluate Xcode 26’s “Sandbox and Hardened Runtime entitlement settings migration” recommendation for the Free Ruler app target.

Suggested scope

• Inspect what Xcode changes when migrating sandbox and hardened runtime entitlement settings to build settings.
• Confirm the existing Free Ruler/Free_Ruler.entitlements file still represents the app’s intended sandbox permissions.
• Keep signing, hardened runtime, and sandbox behavior explicit and easy to audit.
• Verify the app builds, runs, and signs as expected after any migration.

Why

Issue #139 intentionally left this warning as follow-up work because it may change how signing and entitlements are represented. It should be handled separately from the deployment-target/settings cleanup.