Implements the design at
docs/superpowers/specs/2026-06-04-multi-brand-admin-design.md.
Adds:
- admin_user_brands junction table (m:n admin<->brand) via migration 207
- New role 'multi_brand_admin' (auto-set when an admin has 2+ brands)
- 'active_brand_id' cookie that persists the admin's currently-selected
brand across navigations; switchable via the new BrandSelector dropdown
in the sidebar
- Centralised brand resolution in src/lib/brand-scope.ts:
- getActiveBrandId (URL > cookie > legacy brand_id > first of brand_ids)
- assertBrandAccess (defence-in-depth for cases where the brandId
comes from a URL form or RPC return)
- ~30 server actions and ~10 page server components migrated to use
getActiveBrandId instead of the silent brandId ?? adminUser.brand_id
pattern that allowed cross-brand access bugs
- BrandSelector client component with proper a11y (aria-haspopup,
aria-expanded, role=listbox, outside-click and escape-to-close)
Migration 207 also adds RLS so admins can read their own junction rows
(needed for the dropdown to populate) and SECURITY DEFINER RPCs
add/remove_admin_user_brand that auto-promote/demote between
brand_admin and multi_brand_admin.
Notes:
- Migration number is 207 not 204 — 204-206 were taken in this worktree
by the concurrent locations work.
- The legacy admin_users.brand_id column is preserved for backwards
compat; a follow-up migration 220_* will drop it.
- Dev sessions (dev_session cookie, NEXT_PUBLIC_USE_MOCK_DATA) get
brand_ids: []; the documented limitation is that dev store_employee
will see <AdminAccessDenied /> if no real brands exist.
- Pages that hardcode a Tuxedo brand UUID as a fallback
(adminUser.brand_id ?? '64294306-...') are NOT migrated in this PR —
they still work for single-brand admins and are out of scope.
Co-authored-by: implementer subagent (cancelled mid-run), Grok orchestrator
tyler