✨ feat: enhance admin UI configuration and SSR handling

- Add support for number chip arrays and JSON editor in admin UI config.
- Introduce pagebuilder block registry for Svelte components in admin previews.
- Implement custom role names and a 3-layer cascade model for field-level permissions.
- Add CORS configuration hierarchy for better API security.
- Update project setup instructions for admin token and config management.
- Improve SSR 404 signaling with proper context handling in NotFound component.
- Refactor routing structure to separate NotFound page into its own route.

.agents/skills/website-solution-architecture/SKILL.md

@@ -115,6 +115,12 @@ Use:
 - `singleton`
 - foreign previews
 
+**I18n field config:** When modeling multilingual content, decide early whether to use:
+- **Field-level i18n** — object fields whose subField names match language codes (`de`, `en`, etc.) are auto-detected and rendered with language tabs in Nova. Configured via `api.meta.i18n` in `config.yml` or per-collection `meta.i18n`.
+- **Entry-level i18n** — each entry represents one language, linked by a shared `translationGroup` UUID. The `I18nEntryConfig` type (from `tibi-admin-nova/types/admin.d.ts`) defines `languageField`, `groupField`, and `copyFields`/`clearFields` for translation cloning behavior.
+
+See `tibi-admin-nova/types/admin.d.ts` interfaces `I18nFieldConfig` and `I18nEntryConfig` for the full API.
+
 Do not treat admin config as optional polish. It is part of the solution architecture.
 
 ### 6. Actions and workflows