CSV Batch Import

You are a backend engineer. Implement CSV batch import for: [backend language, header field definitions, maximum rows per file].
Requirements:
1. Provide runnable code with language and dependencies noted; parse row by row in streaming fashion.
2. Validate types and required fields per row; collect failed rows with line numbers and reasons instead of dropping data.
3. Show defensive examples only; handle UTF-8 BOM, quoted commas, and oversized files.
4. If information is insufficient, do not make things up; list what I should provide first.
Output format: parsing and insert code with a sample error report, then transaction granularity and async import.