chore(lint): pin ruff 0.15.20, fix pre-existing violations from 0.16.0 upgrade

[JesuFemi-O]

Summary

• Pins ruff==0.15.20 in dev extras so CI and local dev always use the same version
• Switches CI from uvx ruff check (always pulls latest) to uv run ruff check
• Auto-fixes 194 pre-existing violations introduced by ruff 0.16.0's new rules
• Adds E402 ignore for src/tycoon/commands/init.py (import order side-effect of the auto-fix)

Why

CI was using uvx ruff which downloaded ruff 0.16.0 at run time while the project venv had 0.15.20. The version drift caused 299 violations across 54 files that didn't exist locally.

Files to focus on

• pyproject.toml — ruff==0.15.20 added to dev extras, E402 per-file-ignore
• .github/workflows/ci.yml — uv sync --all-extras step + uv run ruff check

Base of the M2 stack — #169 targets this branch.

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[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[db-tycoon-stephen]

Pin and the uvx → uv run switch both look right, and this fixes the real problem of CI drifting from local.

Two changes worth making before this goes into v0.1.11:

Add ruff format --check to the ruff job. CI only runs ruff check, so formatting isn't enforced. src/tycoon/project.py was missed by the format pass here, and the churn is now showing up inside #169 and #171 — #169 is +91/-39 for what's really about 50 lines of new code, which makes the feature diffs harder to read. Enforcing format in CI stops that recurring.

Use uv sync --group dev instead of uv sync --all-extras. ruff is in [dependency-groups], not [project.optional-dependencies], so --all-extras isn't what's installing it — uv's default dev group is. It works, but by accident, and --all-extras pulls every optional extra the project has. Being explicit here means the step keeps working if the default-group behaviour ever changes.

[db-tycoon-stephen]

Claude caught some issues. Can you review them before merging?

[db-tycoon-stephen]

Requesting changes on the two items in the comment above: add ruff format --check to the ruff job so formatting drift stops leaking into feature PRs, and switch uv sync --all-extras to uv sync --group dev so the step names the group that actually provides ruff.

The pin itself and the uvx → uv run switch are right — this is the fix I want, just want those two tightened before it lands in v0.1.11.

[db-tycoon-stephen]

Both addressed — uv sync --group dev with a comment explaining why, and a ruff format --check step. Green across the board. Good to go into v0.1.11.