[Feature]: Show generic info when course doesn't have any program

### What happened?

When course doesnt have a program, we show this : "Aucun programme n'a été trouvé pour ce cours."

### What is the expected behaviour?

Instead, we can use the endpoint `/courses/${id}` to show minimal info about the course.

### Steps to reproduce

1. Pick a course that doesnt have a program (ex: [GPE450](https://planifets.clubapplets.ca/course/351827))

### Screenshots and additional context

Start at the course page for GPE450 and trace the empty-program state. Read the existing course data flow, then inspect the `/courses/${id}` response to determine which minimal course information can be shown. Done means a course without a program displays that information instead of the current French empty-state message.

Written by the indexing model from the issue text.