Import or update knowledge base items from a CSV file. Available from version 257.

CSV format: key, value, expiresAt (optional, ISO 8601 date format)

The import operation will:

• Create new items if the key doesn't exist
• Update existing items if the key exists and values differ
• Skip items that are unchanged
• Fail for items that are used in connectors

Maximum file size: 10,000 rows

Returns a summary with counts of added, updated, and unchanged items.

Possible error codes: FileTooBig, DuplicateKeys, InvalidCsv, ImportFailed