Summary

• Adds frontend validation to prevent saving a chunk overlap value greater than or equal to chunk size
• Shows an inline error message in both the settings page and the cloud-picker ingest settings dialog
• Blocks the save/ingest action until the values are corrected
• Adds backend Pydantic validation to reject invalid chunk configurations at the API level

Test plan

• In Settings page, set Chunk Overlap >= Chunk Size and verify inline error appears and save is blocked
• Fix the values and verify the error clears and save proceeds
• In the upload/ingest dialog, set invalid chunk values and verify error appears before ingestion starts
• Verify valid configurations save and ingest correctly