Backfill critical logs should preserve tracebacks

[kbighorse]

Context

Identified during review of #558 (558-radionuclides-backfill branch).

Problem

The __main__ block in backfill.py catches Exception and logs with an f-string:

logger.critical(f"Backfill orchestration failed: {exc}")

This loses the full traceback, making production failures very hard to diagnose.

Fix

Replace with logger.critical("Backfill orchestration failed", exc_info=True) to preserve the stack trace in log output.

Files

• transfers/backfill/backfill.py (lines 68–69)

[github-actions]

Linked Jira ticket created: BDMS-615

[kbighorse]

Fixed in working tree — critical failure logging now preserves traceback via exc_info=True.

[kbighorse]

Reopened to track completion on base branch. This should stay open until PR #569 is merged (the fix currently lives in that PR diff).