Adopt Ruff

Dependencies

Standalone. No dependencies on other skills.

Overview

Replace legacy Python linting (black, isort, flake8, pylint) with ruff as the sole linter and formatter. Enable ALL rules including preview, explicitly disable what fails, then enforce rules — either progressively (one MR per rule/batch) or by enabling all rules at once and checking only changed files.

Projects that picked "changed files only" accumulate per-file-ignores over time (engineers touch a file, see unrelated violations, pin the rule instead of fixing it). Phase 3 is the recurring, session-sized cleanup that pays that debt back one file or one rule at a time.

Principles