TXT Merger With Excel Report

I keep batches of plain .txt files that need to be packed into a single archive-style file so I can free up space and reduce manual handling. Alongside the merged output, I also want a spreadsheet that captures basic metadata for every source file (file name, original size, creation date/time and any line-count or checksum you find convenient).

Key points
• Input will always be TXT.
• The merge itself can be a simple end-to-end concatenation; no extra separators are necessary unless you feel a minimal delimiter will help the report stay in sync.
• An .xlsx report must be generated automatically in the same run, listing the attributes above and any additional stats you can collect without major overhead.
• The process should complete in memory-efficient fashion; some folders can reach several gigabytes in total.

Please deliver:
1. The working utility or script (Python, C#, Go or another cross-platform language is fine).
2. Source code with brief inline comments.
3. A short README explaining how to run the tool and where each output file will appear.

I’ll test with a live set of roughly 10,000 TXT files and will sign off once the merged file opens correctly and the Excel sheet matches the source list one-to-one.