Replace black/flake8/pylint with ruff

[korbonits]

Summary

• Drops black==22.6.0, flake8==5.0.4, and pylint==2.15.0 from requirements-dev.txt in favor of a single ruff dependency
• Migrates [tool.black] (from pyproject.toml) and [flake8] (from setup.cfg) config into [tool.ruff] / [tool.ruff.lint] / [tool.ruff.format] — preserving the existing line-length = 120, ignored codes (E203, E501), and per-file ignores for __init__.py and hubconf.py
• Removes the now-empty setup.cfg
• Updates .github/workflows/lint.yaml to use ruff check and ruff format --check instead of three separate tool invocations
• Applies ruff format to 19 files whose formatting had drifted from black's output; all other source files are unchanged

Motivation

The current dev toolchain uses three separate tools pinned to versions from 2022. ruff replaces all three, runs 10–100x faster, and is configured in one place (pyproject.toml). There is an open dependabot PR (#589) just to bump black — this supersedes it.

ruff check and ruff format --check both pass cleanly on the full codebase after this change.

Test plan

• pip install -r requirements-dev.txt installs cleanly
• ruff check dinov2 → All checks passed!
• ruff format --check dinov2 → 155 files already formatted
• CI lint workflow passes

🤖 Generated with Claude Code

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