Support uv-managed Python execution

[StevanusPangau]

Summary

Please add first-class support for running graphify with uv.

Problem

graphify currently assumes a plain python3 workflow. In uv-managed environments,
this can cause interpreter mismatches or install/runtime failures.

Request

It would help if graphify could:

• detect and support uv run python
• document uv as a supported workflow
• avoid relying only on python3 resolution

Why

uv run python is often the most reliable interpreter in modern Python setups,
especially when python3 points to a different environment than the one the user
expects.

[biggates]

It is more useful if graphify could detect all virtual environments and let the user select one, as vscode does. or at least detect .venv in project folder.