feat(persons): add formatLifeDateRange + formatDocumentStatus utility functions

Unit tests for both; i18n keys for doc status and person stats bar;
PERSON_NOT_FOUND added to frontend ErrorCode type.

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

frontend/src/lib/utils/documentStatusLabel.spec.ts

@@ -0,0 +1,28 @@
+import { describe, it, expect } from 'vitest';
+import { formatDocumentStatus } from './documentStatusLabel';
+
+describe('formatDocumentStatus', () => {
+	it('maps PLACEHOLDER to correct label', () => {
+		expect(formatDocumentStatus('PLACEHOLDER')).toBe('Platzhalter');
+	});
+
+	it('maps UPLOADED to correct label', () => {
+		expect(formatDocumentStatus('UPLOADED')).toBe('Hochgeladen');
+	});
+
+	it('maps TRANSCRIBED to correct label', () => {
+		expect(formatDocumentStatus('TRANSCRIBED')).toBe('Transkribiert');
+	});
+
+	it('maps REVIEWED to correct label', () => {
+		expect(formatDocumentStatus('REVIEWED')).toBe('Geprüft');
+	});
+
+	it('maps ARCHIVED to correct label', () => {
+		expect(formatDocumentStatus('ARCHIVED')).toBe('Archiviert');
+	});
+
+	it('returns fallback for unknown status', () => {
+		expect(formatDocumentStatus('SOMETHING_NEW')).toBe('Unbekannt');
+	});
+});

frontend/src/lib/utils/documentStatusLabel.ts

@@ -0,0 +1,22 @@
+import { m } from '$lib/paraglide/messages.js';
+
+/**
+ * Maps a document status string to a localised human-readable label.
+ * Falls back to "Unknown" for unrecognised values.
+ */
+export function formatDocumentStatus(status: string): string {
+	switch (status) {
+		case 'PLACEHOLDER':
+			return m.doc_status_placeholder();
+		case 'UPLOADED':
+			return m.doc_status_uploaded();
+		case 'TRANSCRIBED':
+			return m.doc_status_transcribed();
+		case 'REVIEWED':
+			return m.doc_status_reviewed();
+		case 'ARCHIVED':
+			return m.doc_status_archived();
+		default:
+			return m.doc_status_unknown();
+	}
+}

frontend/src/lib/utils/personLifeDates.spec.ts

@@ -0,0 +1,24 @@
+import { describe, it, expect } from 'vitest';
+import { formatLifeDateRange } from './personLifeDates';
+
+describe('formatLifeDateRange', () => {
+	it('returns both dates when birth and death year are given', () => {
+		expect(formatLifeDateRange(1882, 1944)).toBe('* 1882 – † 1944');
+	});
+
+	it('returns only birth year when only birthYear is given', () => {
+		expect(formatLifeDateRange(1882, undefined)).toBe('* 1882');
+	});
+
+	it('returns only death year when only deathYear is given', () => {
+		expect(formatLifeDateRange(undefined, 1944)).toBe('† 1944');
+	});
+
+	it('returns empty string when neither year is given', () => {
+		expect(formatLifeDateRange(undefined, undefined)).toBe('');
+	});
+
+	it('returns empty string when both are null', () => {
+		expect(formatLifeDateRange(null, null)).toBe('');
+	});
+});

frontend/src/lib/utils/personLifeDates.ts

@@ -0,0 +1,20 @@
+/**
+ * Formats the life date range for a person.
+ * Examples:
+ *   * 1882 – † 1944  (both)
+ *   * 1882            (birth only)
+ *   † 1944            (death only)
+ *   ""                (neither)
+ */
+export function formatLifeDateRange(birthYear?: number | null, deathYear?: number | null): string {
+	if (birthYear && deathYear) {
+		return `* ${birthYear} – † ${deathYear}`;
+	}
+	if (birthYear) {
+		return `* ${birthYear}`;
+	}
+	if (deathYear) {
+		return `† ${deathYear}`;
+	}
+	return '';
+}