feat(clients): hard-delete with email-code confirmation (single + bulk)

Permanent client deletion is now reachable from:
- archived single-client detail page (icon button, gated by new
  admin.permanently_delete_clients perm)
- archived clients list bulk action

Both flows are 2-stage: request a 4-digit code (sent to operator's
account email, 10min Redis TTL), then enter both code AND a typed
confirmation (client name single, "DELETE N CLIENTS" bulk). Cascade
strategy preserves audit trails: signed documents, email threads,
files and reminders are detached but retained; addresses, contacts,
notes, portal user, GDPR records, interests and reservations are
deleted via FK cascade or explicit tx delete.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/audit.ts

@@ -23,7 +23,9 @@ export type AuditAction =
   | 'portal_password_reset_request'
   | 'portal_password_reset'
   | 'send'
-  | 'view';
+  | 'view'
+  | 'request_hard_delete_code'
+  | 'hard_delete';
 
 /**
  * Common shape passed to service functions so they can stamp audit logs and