Accept page-centric markdown SoR with dual authoring, live includes, and
lazy projections; accept thin dir+git plane with PageOps and supported
upgrades to shard-wiki and kontextual. Demote ADR-0002 Forgejo-as-SoR.
Introduce tenant-scoped Space/SpaceMembership with list and detail views.
Document markdown-in-Forgejo as content SoR (ADR-0002). Run migrations on
container start so app.coulomb.social picks up the new tables.