Add stuck import detection and retry/cancel options for Bitbucket Server imports
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## Problem
When importing from Bitbucket Server, users see an "Import in progress" page even for stuck imports that were initiated more than 24 hours ago. This creates a poor user experience where:
- The import appears to be taking a long time rather than being stuck
- No indication is given that the import has failed or is stuck
- Users cannot cancel the stuck import
- Users cannot retry the import
## Expected Behavior
The import status should:
- Accurately reflect the import progress
- Allow users to cancel stuck imports
- Allow users to retry failed/stuck imports
- Show appropriate error states instead of indefinite loading
## Current Impact
Users are left waiting indefinitely for imports that will never complete, with no way to resolve the situation or understand what has happened to their import process.
## Potential Improvements
- [ ] Detect when Bitbucket Server imports have been stuck
- [ ] Display appropriate error/stuck status instead of "Import in progress"
- [ ] Provide option to cancel stuck imports
- [ ] Provide option to retry failed/stuck imports
- [ ] Update UI messaging to be clear about import status
issue