[Medium] Add credential access control mechanisms

[Josie123-Dev]

Task Description

Implement credential access control in contracts:

• Define access permissions
• Check access rights
• Implement access grants
• Add access revocation
• Track access history

Requirements

• Permission definition
• Access checking
• Grant logic
• Revocation logic
• History tracking

Acceptance Criteria

• Permissions are defined
• Access is checked
• Grants work
• Revocation works
• History is tracked

[Dev-sandy1]

Good day. Please can i work on these issue.