dominicrume/cantor8_kya_rails: docs/drafts/comment-860-dates.md

The milestones gave relative weeks. They now give dates: 29 December 2026, 26 January, 23 February, 23 March, anchored to signature on or before 1 December and moving together if that slips. PR #943 made that field Committed Date on 29 October and this proposal predated it. One request, and it is…