[Easy] Add credential gas optimization

[Josie123-Dev]

Task Description

Optimize credential contracts for gas efficiency:

• Reduce storage costs
• Optimize function calls
• Minimize event data
• Use efficient data types
• Batch operations where possible

Requirements

• Storage optimization
• Function optimization
• Event optimization
• Data type optimization
• Batch optimization

Acceptance Criteria

• Storage is efficient
• Functions are optimized
• Events are optimized
• Data types are efficient
• Batching is used

[Dev-sandy1]

Good day. Please can i work on these issue.