Feature: Native CSV output format (--csv)

[dlevy-msft-sql]

Summary

Add a --csv flag to output query results in native CSV format.

Use Case

• Export data directly to CSV without needing to set column separator and parse manually
• Integration with data analysis tools (Excel, pandas, etc.)
• Scripting and automation pipelines

Proposed Syntax

sqlcmd -S server -Q "SELECT * FROM users" --csv

Example Output

id,name,email
1,Alice,alice@example.com
2,Bob,bob@example.com

Features

• Proper handling of values containing commas (quote wrapping)
• Proper handling of values containing quotes (escaping)
• Optional header row (controlled by existing -h flag)
• UTF-8 encoding by default

Implementation Notes

• Could leverage existing formatter infrastructure in pkg/sqlcmd/formatter.go
• Consider using Go's standard encoding/csv package for proper RFC 4180 compliance