Fix v2.4.1 launch rejection and prepare v2.4.2

[AlexanderSmyslowski]

Summary

• remove the protected time-sensitive notification entitlement from every build path that lacks a verified provisioning profile
• choose time-sensitive delivery only when the running signature actually exposes the authorized entitlement; otherwise use audible active notifications compatible with Persistent alert style
• add an actual isolated menu-bar launch smoke test and a mutated-package regression test
• publish the correction transparently as v2.4.2 build 26 and mark v2.4.1 superseded

Root cause

v2.4.1 embedded com.apple.developer.usernotifications.time-sensitive in an ad-hoc signature. codesign verification accepted that signature, but macOS denied execution with OS_REASON_EXEC because no Apple-authorized provisioning profile granted the protected capability.

Verification

• make test
• scripts/validate-release.sh v2.4.2
• packaging/verify-pkg.sh --expect-unsigned GDrive-Backup-Tiger-2.4.2.pkg
• Universal 2, codesign verification, entitlement absence, and real process-liveness smoke test