Introduces SpaceType ('personal' | 'brand' | 'club' | 'family' | 'team' |
'practice') and SPACE_MODULE_ALLOWLIST as the shared-branding primitives
for the Spaces refactor that replaces the user-vs-org polymorphy with a
single tenancy primitive (Notion/Linear pattern).
Pure additive — no runtime behaviour change yet. Better Auth config,
Dexie migration, scope wrapper and rolling module migration follow in
separate commits.
Plan: docs/plans/spaces-foundation.md
Social-relay plan now defers brand storage to the Spaces primitive.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
