[2026-04-30][feat][general] implement workspace billing engine with entitlement services, prorated billing logic, and subscription lifecycle management

👤 Author : Matoraaa
🌿 Branch : master
🔗 Commit : 738a278
📅 Date : 2026-04-30
📝 Note :
feat: implement workspace billing engine with entitlement services, prorated billing logic, and subscription lifecycle management