Implement audit logging for patient data changes

[kmuwanga83]

📌 Problem

Changes to patient data are not tracked, which is critical in healthcare systems.

🎯 Objective

Introduce audit logging for accountability and traceability.

✅ Tasks

• Log actions such as:
  • create/update/delete patient records
• Store logs with:
  • timestamp
  • user
  • action
• Provide basic log retrieval endpoint

🧪 Acceptance Criteria

• All key actions are logged
• Logs are stored persistently
• Logs can be queried