Introduce default expiration configuration at the definition and global levels using period-based logic. This supplements the existing issue-level expiration, which remains as a per-approval parameter allowing exact date settings.

Accepted criteria

• Supports setting default expiration at the global level using period-based values

• Supports setting default expiration at the definition level using period-based values

• Issue-level expiration remains unchanged and allows setting exact expiry dates per approval

• Definition-level defaults override global defaults when both are present