feat(web-i18n): add es/fr locales and expand switcher locale set

docs/architecture.md

@@ -7,6 +7,7 @@
 - `packages/db`: prisma + data access
 - `packages/content`: shared schemas and domain contracts
 - `packages/ui`: shared UI layer
+- `packages/i18n`: shared locale definitions and i18n helpers
 - `packages/config`: shared TS config
 
 ## Design Principles
@@ -14,6 +15,7 @@
 - Shared contracts before feature implementation
 - RBAC and CRUD base as prerequisites for MVP1 feature work
 - Keep admin and public responsibilities clearly separated
+- Public routing is path-stable; locale is resolved via `next-intl` middleware + cookie
 
 ## Pending Documentation