Optimized requirements for Python 3.9 (2026 Fixes)

[YellowSM]

This PR adds a stable requirements file optimized for Python 3.9 and legacy hardware (HDD/non-AVX CPUs).

Key fixes:

• Dora 0.0.5: Fixed scikit-learn dependency conflict.
• setuptools < 70.0.0: Restored pkg_resources for librosa compatibility.
• ONNX Conflict: Removed redundant onnxruntime to ensure onnxruntime-gpu works correctly.
• Speed: Improved installation time (8 min vs 26 min on HDD) by adding wheel and ninja.

[Samcfuchs]

This environment fails to build for me:

❯ git remote add yellowsm git@github.com:YellowSM/ultimatevocalremovergui.git
❯ git fetch yellowsm
remote: Enumerating objects: 12, done.
remote: Counting objects: 100% (6/6), done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 12 (delta 3), reused 3 (delta 3), pack-reused 6 (from 1)
Unpacking objects: 100% (12/12), 82.08 KiB | 609.00 KiB/s, done.
From github.com:YellowSM/ultimatevocalremovergui
 * [new branch]      master                       -> yellowsm/master
 * [new branch]      v5.6.0_roformer_add+directml -> yellowsm/v5.6.0_roformer_add+directml
❯ git checkout -b yellowsm yellowsm/v5.6.0_roformer_add+directml
branch 'yellowsm' set up to track 'yellowsm/v5.6.0_roformer_add+directml'.
Switched to a new branch 'yellowsm'
❯ uv venv --python 3.9
Using CPython 3.9.25
Creating virtual environment at: .venv
✔ A virtual environment already exists at `.venv`. Do you want to replace it? · yes
Activate with: source .venv/bin/activate
❯ source .venv/bin/activate
❯ python --version
Python 3.9.25
❯ uv pip install -r requirements.txt
  × No solution found when resolving dependencies:
  ╰─▶ Because asteroid==0.7.0 depends on scipy>=1.10.1 and you require scipy==1.9.3, we can conclude that your requirements and asteroid==0.7.0 are incompatible.
      And because you require asteroid==0.7.0, we can conclude that your requirements are unsatisfiable.