fix: resolved doctor login

🩺 Restrict Doctor Login to Camp-Registered Users

Overview

This MR fixes an issue where doctors who were not registered for a medical camp were still able to log in and be marked as available. This caused incorrect data in downstream flows such as specialization selection.

---

❗ Problem

• Unregistered doctors could log in from the Doctors Directory.

• Backend was automatically creating a CampVisit record with:

  • attendance = True
  • login_time set

• As a result:

  • These doctors appeared as available
  • Their specializations showed up in patient assignment (incorrect behavior)

---

✅ Solution

Updated the update_user_attendance logic in:

app/services/medical_camp_service.py

New Behavior:

• If a doctor attempts to log in:

  • ❌ Reject if no CampVisit record exists
  • ❌ Reject if signup = False (not registered)

• Only allow login when:

  • ✅ CampVisit exists AND signup = True

---

🔐 Impact

• Ensures only camp-registered doctors can log in
• Prevents invalid availability states
• Keeps specialization dropdown accurate (only registered + logged-in doctors)

---

🧪 Test Cases

1. Unregistered Doctor Login

   • Attempt login without camp registration
   • Expected: ❌ Rejected with error message

2. Registered Doctor Login

   • Register doctor → login
   • Expected: ✅ Success, status = Available

3. Specialization Validation

   • Only registered + logged-in doctors appear in specialization dropdown

---

💬 Backend Response

Returns:

"Doctors must be registered for the camp before logging in."

---

📌 Notes

• No changes required in frontend for enforcement (backend validation is strict)
• Frontend can optionally disable login button for better UX

---