3.1.0 — pure pip install: madmom replaced by madmom-infer

• madmom replaced by madmom-infer: installation is now plain pip install all-in-one-infer — no git installs, no post-install hooks. Verified: correctly-rounded STFT magnitude (1 ULP fix over madmom's np.abs bug) closure-proven, and end-to-end on 3 real songs all discrete outputs (bpm/beats/downbeats/segments) were exactly identical
• Fixed a fresh-install crash on torchaudio ≥2.11 (missing torchcodec decoders): wav/flac input loading now goes through soundfile (proven bit-identical), mp3 stays on torchaudio
• demucs-infer bumped to >=4.2.2 (brings its own torchaudio-2.11 fix)
• Revived 3 E2E tests (test_analyze/test_sonify/test_visualize) that were silently dead since the 3.0.0 rename (stale imports)
• Removed setup.py — its post-install madmom hook never actually fired under pip/uv