feat: auto-detect GPU in setup scripts, log environment at startup

- setup-windows.ps1 and setup_env.sh detect nvidia-smi for CUDA vs CPU PyTorch
- Startup logs Python version, venv path, PyTorch/CUDA/GPU, scikit-learn, librosa

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main.py

@@ -2149,7 +2149,30 @@ class _KeyFilter(QObject):
         return super().eventFilter(obj, event)
 
 
+def _log_env():
+    """Log Python environment info at startup."""
+    _log(f"Python {sys.version}")
+    _log(f"venv: {sys.prefix}")
+    try:
+        import torch
+        cuda = torch.cuda.get_device_name(0) if torch.cuda.is_available() else "not available"
+        _log(f"PyTorch {torch.__version__} — CUDA {torch.version.cuda or 'n/a'} — GPU: {cuda}")
+    except ImportError:
+        _log("PyTorch: not installed")
+    try:
+        import sklearn
+        _log(f"scikit-learn {sklearn.__version__}")
+    except ImportError:
+        _log("scikit-learn: not installed (training will fail)")
+    try:
+        import librosa
+        _log(f"librosa {librosa.__version__}")
+    except ImportError:
+        _log("librosa: not installed")
+
+
 def main():
+    _log_env()
     # Force desktop OpenGL (not GLES) so mpv's render context produces non-black output.
     # Must be set before QApplication.
     from PyQt6.QtGui import QSurfaceFormat

setup-windows.ps1

@@ -25,9 +25,16 @@ $hasTorch = python -c "import torch" 2>&1
 if ($LASTEXITCODE -eq 0) {
     Write-Host "`nPyTorch already installed, skipping." -ForegroundColor Green
 } else {
-    Write-Host "`nInstalling PyTorch with CUDA 12.8..."
-    Write-Host "(For CPU-only: pip install torch torchaudio --index-url https://download.pytorch.org/whl/cpu)" -ForegroundColor Yellow
-    pip install torch torchaudio --index-url https://download.pytorch.org/whl/cu128
+    # Detect NVIDIA GPU via nvidia-smi
+    $hasNvidia = Get-Command nvidia-smi -ErrorAction SilentlyContinue
+    if ($hasNvidia) {
+        Write-Host "`nNVIDIA GPU detected — installing PyTorch with CUDA 12.8..." -ForegroundColor Green
+        pip install torch torchaudio --index-url https://download.pytorch.org/whl/cu128
+    } else {
+        Write-Host "`nNo NVIDIA GPU detected — installing CPU-only PyTorch..." -ForegroundColor Yellow
+        Write-Host "(Audio scanning will work but will be slower without GPU)" -ForegroundColor Yellow
+        pip install torch torchaudio --index-url https://download.pytorch.org/whl/cpu
+    }
 }
 
 # ── Python deps ───────────────────────────────────────────

setup_env.sh

@@ -15,8 +15,14 @@ PYTHON_VERSION="3.12"
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 VENV_DIR="$SCRIPT_DIR/.venv"
 
-# CUDA version for PyTorch index URL
-TORCH_INDEX="https://download.pytorch.org/whl/cu128"
+# Auto-detect GPU for PyTorch index URL
+if command -v nvidia-smi &>/dev/null; then
+    TORCH_INDEX="https://download.pytorch.org/whl/cu128"
+    echo "NVIDIA GPU detected — will install PyTorch with CUDA 12.8"
+else
+    TORCH_INDEX="https://download.pytorch.org/whl/cpu"
+    echo "No NVIDIA GPU detected — will install CPU-only PyTorch"
+fi
 
 # ── Parse args ────────────────────────────────────────────────────────