Simplify toolchain by consolidating Black and isort into Ruff

[z80020100]

Background

The current code quality toolchain has functional overlap between three formatting/linting tools:

Tool	Purpose	Overlap
Ruff	Linter + Formatter (primary)	ruff format is Black-compatible; I rules handle isort
Black	Formatter (fallback)	Fully covered by ruff format
isort	Import sorting	Fully covered by Ruff I lint rules

In pre-commit hooks, ruff-format, black, and isort all run sequentially — producing the same result with redundant processing.

Proposed Changes

Remove Black and isort and keep Ruff + MyPy only.

pyproject.toml

• Remove black and isort from [dependency-groups] dev
• Delete [tool.black] section
• Delete [tool.isort] section

.pre-commit-config.yaml

• Remove black hook (https://github.com/psf/black)
• Remove isort hook (https://github.com/pycqa/isort)

.vscode/settings.json

• Change default formatter from ms-python.black-formatter to charliermarsh.ruff

Result

• No functional change — formatting rules and import sorting behavior remain identical
• Fewer dev dependencies (2 fewer packages)
• Faster pre-commit runs (fewer redundant passes)
• Single source of truth for formatting configuration ([tool.ruff] / [tool.ruff.format])