chore(linting): replace black, isort and flake8 with ruff

[cagyirey]

📝 Change Type

• chore: Updating linting rules
• refactor: Introduces linting changes that will make safe stylistic changes to adhere to standard code hygiene rules. Adds ruff and deprecates autoflake, isort, and black.

💡 Description

Consolidate Python linting and formatting into Ruff - a single, fast tool that replaces autoflake, isort, Black, and flake8.

Why Ruff?

• 10-100x faster than Black/flake8 (Rust-based)
• Single tool replaces 4 dependencies (autoflake, isort, black, flake8)
• Better auto-fixes with more comprehensive lint rules
• Wide adoption - used by FastAPI, Pydantic, Pandas, NumPy, etc.
• Astral ecosystem - same team behind uv, enabling tighter toolchain integration in future PRs

Key Changes

1. Add ruff.toml with unified linting/formatting configuration
2. Update .pre-commit-config.yaml to use ruff hooks (v0.14.6) instead of autoflake/isort/black
3. Remove black, isort from dev dependencies; update ruff>=0.14.6
4. Remove [tool.black], [tool.isort], [tool.ruff] sections from pyproject.toml (now in ruff.toml)

Configuration Details

Preserved from existing config:

• Line length: 100
• isort profile: Black-compatible
• Excluded: src/parallax/p2p/proto/ (generated protobuf)

New lint rules enabled:

Rule Set	Purpose
E, W, F	pycodestyle + Pyflakes (existing)
I	isort import sorting
N	PEP 8 naming conventions
UP	pyupgrade - modernize syntax
B	flake8-bugbear - common bugs
C4	flake8-comprehensions
SIM	flake8-simplify
RUF	Ruff-specific rules
TID	Tidy imports
ASYNC	Async/await best practices

Deferred rules (extend-ignore):
Some rules require larger refactoring and are deferred to follow-up PRs:

• PTH (pathlib migration), TCH (TYPE_CHECKING imports), B006 (mutable defaults)
• N802/803/806 (naming - often intentional for math notation)
• See ruff.toml for full list with rationale

✅ Checklist

• I have performed a self-review of my own code.
• I have added/updated tests that prove my fix or feature works (if applicable).
• I have updated the documentation (if necessary).
• My code follows the project's style guidelines.

📋 Test Plan

• pre-commit run --all-files passes locally after rules are approved
• Maintainers approve or request changes to the linting rules in ruff.toml
• .github/workflows/pre-commit.yml validates linting in CI
• Existing tests continue to pass