fix: use sched_getaffinity for container-aware CPU count

app.py

@@ -32,7 +32,10 @@ from music_detector import _get_ast_runtime, judge_chunk_files_batched
 # Constants
 # ---------------------------------------------------------------------------
 
-N_CPUS = os.cpu_count() or 2
+try:
+    N_CPUS = len(os.sched_getaffinity(0))   # container-aware (Linux cgroup)
+except AttributeError:
+    N_CPUS = os.cpu_count() or 2            # macOS / Windows fallback
 torch.set_num_threads(N_CPUS)
 
 BATCH_SIZE      = 32