Scanner indexes quiz files found next to videos ([&] questions, "- "
options, "-- Correct" markers; _notsolved twins ignored). Quizzes appear
in the folder content list interleaved with videos by filename order.
New api/quiz.php serves questions without answers and grades attempts
server-side; per-user best/last score and attempts stored in
quiz_progress. Folder/course progress now aggregates videos + quizzes
with partial credit for partial scores.
Harwinder Sekhon