[prathshenoy]

Summary

What:

• Save the exact issue change a worker must finish alongside the queue’s progress.
• Add a database upgrade that preserves existing progress.

Why:

• Save exactly which issue change must finish before moving on to newer work. A scan cursor only tells us how far we have read; it cannot tell a replacement worker whether an issue was updated but its history was never written. Saving the intended change first gives that worker the information needed to finish the same work.
• Preserve the issue version that the change was originally allowed to update. A retry must not read a newer version and use it to force an old change through. Only one pending change is needed at a time, so recovery does not require saving an entire batch.

Test Plan

• Add unit tests.
• Verify saved-change persistence, clearing, guarded updates, and upgrading existing progress rows against MySQL.

Revert Plan

• Revert dependent controllers first, then this PR. Leave the added columns in place; no runtime consumer is enabled and existing progress is preserved.

Issue Links

• CODEM-607

Stack

1. feat(stovepipe): Retain versioned issue state #942
2. feat(stovepipe): Save pending issue changes #943
3. feat(stovepipe): Apply saved issue changes #932
4. feat(stovepipe): Track issues in bounded passes #940
5. feat(stovepipe): Publish issue-tracking updates #939