pre-commit: ruff-check fails with real lint errors (F841/E402/F821) in non-template scripts

[scottschreckengaust]

Part of #213.

Problem

ruff-check (configured with --fix --exit-non-zero-on-fix) reports genuine lint violations in tracked, non-template Python files. Error codes observed: F841 (assigned-but-unused), E402 (import not at top), F821 (undefined name).

Affected files (non-template)

plugins/deploy-on-aws/scripts/lib/post_process_drawio.py
plugins/sagemaker-ai/skills/finetuning/templates/rlvr_reward_function_source_template.py
plugins/sagemaker-ai/skills/model-evaluation/scripts/reward_function_source_template.py
tools/validate-urls.py

(Note: the code_templates/*.py files also appear in ruff output but are covered separately by #214 — they fail to parse rather than lint.)

Reproduce

mise exec -- pre-commit run ruff-check --all-files

Proposed fix

Triage each finding: F821 (undefined name) may be a real bug worth verifying; F841/E402 are typically safe to fix directly or via ruff check --fix. For the *_source_template.py files that are code fragments, consider a per-file # ruff: noqa or excluding them if they are not standalone modules.

_{Filed with assistance from Claude Code while implementing #211.}