Fix comfy-cli install --cpu still installs CUDA version of PyTorch

[Xyc2016]

Fixes #344

Tested

• Environment: WSL2 Ubuntu 24.04, Python 3.12.3
• Install Command:
  comfy --skip-prompt install --cpu --skip-manager --url https://github.com/comfyanonymous/[email protected]
  ✅ Installs CPU-only PyTorch
• Minimal ComfyUI workflow on CPU:
  1. Load Image
  2. Custom torch operation (image duplication + horizontal concat)
  3. Preview Image
     ✅ CPU-only torch operations work as expected

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
comfy_cli/command/install.py	0.00%	3 Missing ⚠️

@@            Coverage Diff             @@
##             main     #345      +/-   ##
==========================================
- Coverage   52.18%   52.14%   -0.05%     
==========================================
  Files          32       32              
  Lines        3516     3519       +3     
==========================================
  Hits         1835     1835              
- Misses       1681     1684       +3     

Files with missing lines	Coverage Δ
comfy_cli/command/install.py	57.29% <0.00%> (-0.38%)	⬇️

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[bigcat88]

The real fix for a real bug - merging. 🚀