[`ruff`] Handle argfile expansion errors gracefully (#20691)
<!--
Thank you for contributing to Ruff/ty! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title? (Please prefix
with `[ty]` for ty pull
requests.)
- Does this pull request include references to any relevant issues?
-->
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Fixes #20655
- Guard `argfile::expand_args_from` with contextual error handling so
missing @file arguments surface a friendly failure instead of panicking.
- Extract existing stderr reporting into `report_error` for reuse on
both CLI parsing failures and runtime errors.
## Test Plan
<!-- How was it tested? -->
Add a regression test to integration_test.rs.
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
