feat: passwordless registration — defer account creation to approval

Removes password from the volunteer registration form. Account
creation is now deferred to the approval step:

Backend:
- Registration creates Person without User (user_id=null)
- On approval, system finds or creates User by person.email
- New accounts get a "set password" email with activation link
- Existing accounts get a portal link email
- Added registration_source column to persons (self/organizer)
- Fuzzy name matching skipped for self-registered persons
- person.email is always source of truth for account linking

Frontend:
- Registration form no longer collects password
- Email check shows info alert with login suggestion
- New wachtwoord-instellen.vue page for account activation
- PasswordRequirements.vue component (reused on reset page)
- Success page updated with activation messaging

Tests: 837 passed (all updated for new flow)

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

apps/portal/src/plugins/1.router/guards.ts

@@ -2,7 +2,7 @@ import type { Router } from 'vue-router'
 import { useAuthStore } from '@/stores/useAuthStore'
 import { usePortalStore } from '@/stores/usePortalStore'
 
-const guestOnlyPaths = ['/login', '/wachtwoord-vergeten', '/wachtwoord-resetten', '/verify-email-change']
+const guestOnlyPaths = ['/login', '/wachtwoord-vergeten', '/wachtwoord-resetten', '/wachtwoord-instellen', '/verify-email-change']
 
 // Old dashboard routes that need backward-compat redirects
 const dashboardRedirects: Record<string, string> = {