Fix CSV import: Trading 212 files fail post-correction with generic errors

What went wrong? After correcting initial symbol/field issues, importing Trading 212 CSV exports repeatedly fails with a generic error. The same data imports successfully only after support converts the files, indicating a defect in the original CSV processing path. Where is it happening? Platform: Web Browser or device: Microsoft Edge (latest), Google Chrome (latest) Steps to reproduce: Export trades from Trading 212 as a CSV. Upload the CSV to the platform's CSV importer. Address the initial symbol/field validation issues as instructed and re-upload the corrected file. Observe a generic failure message. Retry with a freshly exported CSV and in both Edge and Chrome; the failure persists. Import a support-converted version of the same CSV; the import succeeds. Expected result: After field corrections, the importer should successfully process the original Trading 212 CSV, or provide clear, actionable row/column-specific validation errors. Actual result: A generic "Import failed" / "Something went wrong" message is shown with no details. Only the support-converted CSV imports successfully, suggesting a parsing/validation defect with the original CSV path (e.g., encoding, delimiter/quoting, headers, or format handling). Screenshot, screen recording, or error message: Error message displayed: "Import failed" / "Something went wrong" (no additional detail).