Summary

Improve the CMS CSV import process with better performance, correct item ordering, rich-text image support, and DRY refactoring across import-related code.

Changes

• Add rich-text image downloading and embedding during CSV import
• Deduplicate assets by filename before downloading to avoid redundant uploads
• Compute content_hash before bulk insert to eliminate N sequential update queries
• Fix manual_order assignment to append imported items after existing ones
• Preload server-sorted collections with correct order to prevent UI flash
• Make enrichItemsWithStatus resilient to transient network errors
• Support includeAssets parameter on items API for returning asset data alongside items
• Extract getSortParams utility and ErrorBanner component to reduce duplication
• Increase asset download concurrency to 20 parallel fetches
• Add proper progress bar with indeterminate state and real-time row counts
• Prevent dialog close and page reload during active import
• Filter computed fields from CSV import mapping options

Test plan

• Import a CSV with image URLs and verify assets are downloaded and linked
• Import a CSV with rich-text HTML containing <img> tags and verify images appear in CMS items
• Re-import the same CSV and verify assets are deduplicated (not re-uploaded)
• Import into a collection that already has items and verify new items appear after existing ones in manual order
• Sort a collection by ID desc, reload the builder, and verify correct order without flash
• Close the browser tab during import and verify the warning prevents accidental closure
• Import a large CSV (50+ rows with images) and verify progress bar updates correctly
• Verify computed fields (e.g., Status) do not appear in the column mapping step
• Check links are working on images (when imported or not, for both URLs and Pages)