Show users a history of their imports with batch details

Track all your data imports with a comprehensive history showing batch details.

Features:

• List all import batches aggregated by batchId

• Display import date, source (CSV/statement-parser), transaction count, and target account

• Click on any batch to view/filter its transactions

• Link to undo functionality for easy rollback

Implementation: New endpoint to list import batches with aggregated metadata, UI to display history and navigate to batch transactions.