Simplification of venv configuration scripts and delegation to a Python script

[nedfreetoplay]

Simplify the virtual-environment setup by replacing large, platform-specific interactive shells with small delegating wrappers and a single cross-platform Python setup script.

What I changed

• Replaced the bulk of the old interactive logic in setup_venv.bat with a minimal Windows wrapper that finds Python and delegates to setup_venv.py.

• Replaced the bulk of the old interactive logic in setup_venv.command with a minimal macOS wrapper that locates Python and execs setup_venv.py.

• Added setup_venv.py: a cross-platform, interactive Python script that:

• prints the banner and checks Python,
• confirms/recreates the venv directory,
• supports simple and advanced install flows,
• allows selecting Qt/mpv/OpenCV/dev/future options,
• creates the venv and installs dependencies (via pip) using package extras.

• Removed many static requirements files and the top-level requirements.txt, consolidating dependency groups into pyproject.toml:

• added dependency-groups and project.optional-dependencies entries (e.g. qt6-new, mpv-new, opencv-new, dev, etc.) so installs use package extras instead of scattered requirement files.

• Updated .gitignore to ignore common build artifacts (*.egg-info/, dist/, build/).

Why

• Single, maintainable entrypoint for venv creation and dependency installation reduces duplication and divergence across platform scripts.

• Moving to pyproject.toml optional-dependencies / dependency-groups centralizes package metadata, making it simpler to install configurable dependency sets via package extras (and easier to keep synced).

• A Python-based installer improves cross-platform behavior, error handling, and is easier to extend and test than complex shell/batch logic.

User-facing notes / upgrade steps

• The public entrypoints remain the same: run setup_venv.bat on Windows or setup_venv.command on macOS — these now delegate to python tools/setup_venv.py.

• You can run the new installer directly: python tools/setup_venv.py.

• requirements.txt and many per-platform requirement files have been removed; use package extras from pyproject.toml, e.g.:

• pip install .[qt6-new,mpv-new,opencv-new]

• After the installer finishes, activate the venv as usual:

• Windows: venv\Scripts\activate.bat
• Unix/macOS: source venv/bin/activate

Testing / verification

• Run the installer on target platform and verify:

• venv is created,
• python -m pip list shows installed extras,
• the client can be started from the created venv.

• If an advanced custom Qt version is required, use the interactive w option (the script will attempt to install the specified PySide6/qtpy versions).

[hydrusnetwork]

Hey, thank you for submitting this. I don't normally like to take pull requests, but this is a great step forward. Merging the script into the one shared .py is great, and using just the pyproject.toml is something I wanted to look into and you've done it all.

I won't merge right now, but I'll revisit next Saturday. Looks great.