docs: M1 and M2 marked done with tags
Updated Development Plan (markdown)
docs: drop ordering-constraints section
docs: M6/M7/M8 rows in milestones table; drop commit count
docs: fold M6 integrations into milestones table
docs: rescope development plan to MVP — defer keyless integrations to M6
docs: wiki — Home, Architecture, Development Plan Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>