Optimize task retention from 5 minutes to 30 seconds to reduce polling overhead since toast notifications are shown only once. Add conditional warehouse pricelist creation via checkbox. Fix category storage in warehouse pricelists to properly load from lot table. Replace SSE with task polling for all long operations. Add comprehensive logging for debugging while minimizing noise from polling endpoints.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
- Added background task manager with goroutine execution and panic recovery
- Replaced SSE streaming with background task execution for:
* Price recalculation (RecalculateAll)
* Stock import (ImportStockLog)
* Pricelist creation (CreateWithProgress)
- Implemented unified polling for task status and DB connection in frontend
- Added task indicator in top bar showing running tasks count
- Added toast notifications for task completion/error
- Tasks automatically cleaned up after 10 minutes
- Tasks show progress (0-100%) with descriptive messages
- Updated handler constructors to receive task manager
- Added API endpoints for task status (/api/tasks, /api/tasks/:id)
Fixes issue with SSE disconnection on slow connections during long-running operations
