[pylint] Implement too-many-lines (C0302)

[tluolamo]

Summary

• Add Pylint too-many-lines (C0302) as a preview physical-lines rule with a 1000-line default, configurable via lint.pylint.max-module-lines.
• Wire the rule into the linter registry/checker, remove the old flake8 file-length plumbing, and expose the new setting in workspace options and schema.
• Add inline rule tests and regenerate docs/schema.

Test Plan

• cargo test -p ruff_linter --lib
• cargo dev generate-all

[ntBre]

Thanks for working on this! However, I see that this rule is crossed out in the summary of #970 with the note "not compatible with the formatter," so I don't think we want to add this rule.