Merge September's daily diary files into one Markdown file in date order with a ' date' heading per day.

Merge September's daily diary files into one Markdown file in date order with a ' date' heading per day.: a task in agent-harbor-tasks (Harbor dataset). Ho il diario in /workdir/diario, un file per giorno. Uniscimi tutto settembre 2026 in /workdir/diario/settembre 2026.md: per ogni giorno una riga…