feat: email infrastructure frontend — settings, templates, and log tabs

Adds three new tabs to the organisation settings page:

- E-mail opmaak: replaces old EmailBrandingTab to use the new
  organisation_email_settings API (logo, colors, footer, reply-to)
- E-mail templates: list/edit/preview/test/reset all 6 template types
  with variable hints, defaults comparison, and iframe preview
- E-mail log: server-side paginated table with filters (search, status,
  type, date range), status chips, and expandable row details

Supporting files:
- types/email.ts: TypeScript interfaces for settings, templates, logs
- composables/api/useEmail.ts: TanStack Query hooks for all email endpoints

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/app/components.d.ts

@@ -59,6 +59,8 @@ declare module 'vue' {
     EditPersonDialog: typeof import('./src/components/persons/EditPersonDialog.vue')['default']
     EditSectionDialog: typeof import('./src/components/sections/EditSectionDialog.vue')['default']
     EmailBrandingTab: typeof import('./src/components/organisation/EmailBrandingTab.vue')['default']
+    EmailLogTab: typeof import('./src/components/organisation/EmailLogTab.vue')['default']
+    EmailTemplatesTab: typeof import('./src/components/organisation/EmailTemplatesTab.vue')['default']
     EnableOneTimePasswordDialog: typeof import('./src/components/dialogs/EnableOneTimePasswordDialog.vue')['default']
     ErrorHeader: typeof import('./src/components/ErrorHeader.vue')['default']
     EventMetricCards: typeof import('./src/components/events/EventMetricCards.vue')['default']