Improve Sign-Off UI to Clearly Indicate When a Sign off trigger a Shipping Phase

[gabrielBusta]

Currently, product teams may sign off on a release without fully considering whether it is actually ready to ship. The sign-off process should clearly indicate that a sign off means “Yes, this is ready to ship.”

We could update the UI to reinforce that sign-off explicitly confirms readiness to ship.

This could include:

• Clearer messaging in the UI (e.g., "By signing off, you confirm this release is ready to ship.")
• A confirmation prompt before signing off.
• Visual indicators to differentiate the final sign-off that triggers a release phase.