Clinic Appointment Scheduling API

A medical clinic needs a REST API to manage appointment scheduling. The system tracks doctors, patients, and appointments. Each appointment belongs to one doctor and one patient, and has a date/time, duration, and status (scheduled, completed, cancelled).

The API needs to support:

• Listing available doctors
• Viewing a doctor's schedule for a given date
• Booking an appointment for a patient with a specific doctor
• Cancelling an appointment
• Viewing a patient's upcoming appointments

The clinic requires that appointment times don't overlap for the same doctor. If someone tries to book a time slot that's already taken, the system should return an appropriate error. Similarly, looking up a doctor or patient that doesn't exist should return a clear error.

All database and application settings should be stored in configuration files. The application should serve a simple static booking page. A test project should be included.

Output

Produce the project under ClinicApi/ with tests in ClinicApi.Tests/. Each file should contain valid C# code with correct namespaces and class/method declarations. Placeholder logic is acceptable but the project structure and class skeletons must be complete.

Include a project-structure.txt file at the root listing the directory tree.