Show absolute epoch number in resume progress bar

[dxqb]

Summary

The epoch progress bar iterated range(resume_epoch, total_epochs) with no initial/total, so on resume it showed the count of remaining epochs starting from 0 (e.g. 1/50) instead of the absolute position (51/100). This adds initial=train_progress.epoch, total=self.config.epochs, matching how the step bar just below it already resumes.

Cosmetic only -- train_progress.epoch and the LR schedule were already correct; this only fixes the display. Surfaced while investigating #1604.

Test plan

• pre-commit run --all-files passes
• Launched the affected UI or script and exercised the change
• Tested with at least one real preset / config when relevant (note which: ____)

AI assistance

• AI-assisted -- I have read every line in this diff and can defend each change