* fix(#2279): reword date stamping to overwrite existing dates on Update runs The map-codebase agent and workflow instructions only said to replace [YYYY-MM-DD] placeholders, but Update-path files already contain concrete dates from the prior run. Reword to SET the date stamps unconditionally, overwriting whatever date is already there. Closes #2279 * docs(#2279): backfill changeset PR number (2550)