feat(setup): event-types step in first-run wizard + un-hardcode event type deps (#800)

Fresh installs can now shape the event-type catalog during the setup
wizard — rename, delete or replace the seeded defaults while nothing
references them. On existing installs system types stay protected.

- New wizard step between features and config: edit name/URL prefix,
  remove, or add types; defaults shown as recommendations
- setup_wizard_completed app setting (migration 161): seeded true when
  an admin already exists, false on fresh installs; POST /api/setup/
  complete (adminAuth) flips it when the wizard finishes
- deleteEventType: system types deletable only while the flag is unset;
  in-use check extended to quotes; per-type reminder template
  (event_reminder_<slug>) is deleted with the type
- reminder-template self-heal no longer resurrects templates for slugs
  removed from the catalog
- v1 API event creation validates event_type against the live catalog
  instead of a hardcoded whitelist (custom types were rejected; the
  never-seeded 'family' slug is no longer silently accepted)
- contract→event conversion resolves the event type via
  crm_default_event_type / resolveDefaultEventType instead of
  hardcoding 'wedding' (resolveDefaultEventType moved from quoteService
  to eventTypeService for reuse)

frontend/src/services/setup.service.ts

@@ -38,4 +38,11 @@ export const setupService = {
     const response = await api.post<{ user: SetupAdminUser }>('/setup/admin', input);
     return response.data;
   },
+
+  // One-way wizard-finish marker (authenticated — runs after the admin
+  // exists). While unset, the wizard's event-types step may delete the
+  // seeded system types; afterwards they are permanently protected.
+  async completeSetup(): Promise<void> {
+    await api.post('/setup/complete');
+  },
 };