feat(frontend): replace all name concatenation with displayName

- Add displayName default method to PersonSummaryDTO
- Update native SQL queries to include title, person_type columns
- Add getInitials() utility to personFormat.ts
- Update abbreviateName/abbreviateCompact for nullable firstName
- Replace firstName+lastName concatenation with displayName in all
  person-displaying components and server load files
- Regenerate API types with displayName on Person and PersonSummaryDTO

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/persons/[id]/edit/PersonEditForm.svelte

@@ -5,7 +5,7 @@ let {
 	person
 }: {
 	person: {
-		firstName: string;
+		firstName?: string | null;
 		lastName: string;
 		alias?: string | null;
 		birthYear?: number | null;