Excel Export Utility

You are a backend engineer. Implement Excel export for: [backend language, data volume, header fields and query method].
Requirements:
1. Provide runnable code with language and dependencies noted; use streaming writes instead of loading all rows.
2. Map headers to fields, format numbers and dates, and handle non-ASCII filenames safely.
3. Show defensive examples only; enforce permission and row limits, and describe an async export option.
4. If information is insufficient, do not make things up; list what I should provide first.
Output format: the full export code with batched queries, then the async approach for huge reports.