[alandarev]

Summary

Scenes request their music every frame and rely on PlayMusic() doing nothing
while that track plays. A track that cannot be opened never becomes the current
one, so every request opened the file again — the decoder probe ran on the main
thread and another failed to init stream line went to the log on every frame,
as #584 describes (and on macOS the synchronous stream init could hang the main
thread).

MiniAudioBackend now remembers the last track that failed and skips plain
requests for it. It is tried again when another track is requested in between,
when the request is enforced, or after all music or that track was stopped
(turning the music off and on stops all of it); the per-frame stops of other
maps' tracks leave it alone. The destructor's Shutdown() call is qualified so
Cppcheck's virtualCallInConstructor is satisfied for the touched file
(behaviour unchanged).

Related issues

Closes #584.

Testing

• Two unit tests with a no-device engine (tests/core/test_audio_playback.cpp):
  a missing track is not reopened by plain requests or other tracks' stops, and is
  reopened after another request, an enforced request or a stop. The first fails
  without the fix.
• ctest: 455/455; clang-format 21.1.8 and Cppcheck with the CI options: no findings.
• In the game with music on and no Data/Music folder, logging in and visiting
  Lorencia, Devias and Noria: before, 307–350 failed to init stream lines per
  track; after, one per track and visit.

Written with AI assistance and tested by hand.

Checklist

• I have read and followed docs/CODING_RULES.md.
• I have built the project locally (see docs/build/README.md).
• Changes are focused on one concern; the diff is as small as it reasonably can be.

[alandarev]

Closing as superseded by 122cc57, merged into main via #610. Upstream now keeps failed music tracks cached for the audio session, including named stop/replay loops in Balgass Barracks/Refuge and Cursed Temple. This also covers the edge case identified in this PR, so keeping upstream’s stronger implementation instead of duplicating it.