feat(cards): typing Card-Type mit Fuzzy-Match

- typing.ts: checkTypingAnswer (exact / close / wrong) + Levenshtein-
  Impl; close = Distanz ≤ max(1, floor(len * 0.2)); Alias-Support via
  komma-separiertes aliases-Feld
- CardTypeSchema: 'typing' ergänzt; validateFieldsForType: front+answer required
- subIndexCount: 'typing' → 1
- TypingView.svelte: Input-Feld + Submit + Result-Badge + Antwort-Markdown +
  kontext-spezifische Grade-Buttons (correct: Weiter; close: Nochmal/War richtig;
  wrong: volle 4 Buttons); svelte:window für Keyboard
- Study-Page: TypingView eingebunden, Action-Bar bei typing ausgeblendet,
  onKey delegiert zu TypingView

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

packages/cards-domain/src/fsrs.ts

@@ -149,6 +149,8 @@ export function subIndexCount(type: string): number {
 			);
 		case 'audio-front':
 			return 1;
+		case 'typing':
+			return 1;
 		case 'multiple-choice':
 			return 1;
 		case 'cloze':

packages/cards-domain/src/index.ts

@@ -13,3 +13,4 @@ export * from './protocol/index.ts';
 export * from './cloze.ts';
 export * from './content-hash.ts';
 export * from './image-occlusion.ts';
+export * from './typing.ts';

packages/cards-domain/src/schemas/card.ts

@@ -11,6 +11,7 @@ export const CardTypeSchema = z.enum([
 	'cloze',
 	'image-occlusion',
 	'audio-front',
+	'typing',
 ]);
 export type CardType = z.infer<typeof CardTypeSchema>;
 
@@ -48,6 +49,7 @@ export function validateFieldsForType(
 		'type-in': ['question', 'expected'],
 		'image-occlusion': ['image_ref', 'mask_regions'],
 		'audio-front': ['audio_ref', 'back'],
+		typing: ['front', 'answer'],
 		'multiple-choice': ['question', 'options', 'correct_index'],
 	};
 	const need = required[type] ?? [];

packages/cards-domain/src/typing.ts

@@ -0,0 +1,49 @@
+export type TypingMatchResult = 'correct' | 'close' | 'wrong';
+
+/**
+ * Vergleicht eine getippte Antwort mit der erwarteten Antwort.
+ * Normalisiert: lowercase, trim, NFD-Diakritika-Stripping.
+ * "close" = Levenshtein-Distanz ≤ max(1, floor(answer.length * 0.2)).
+ */
+export function checkTypingAnswer(
+	input: string,
+	answer: string,
+	aliases?: string,
+): TypingMatchResult {
+	const norm = (s: string) =>
+		s
+			.trim()
+			.toLowerCase()
+			.normalize('NFD')
+			.replace(/\p{Mn}/gu, '');
+
+	const normInput = norm(input);
+	const candidates = [answer, ...(aliases ? aliases.split(',') : [])]
+		.map(norm)
+		.filter((s) => s.length > 0);
+
+	if (candidates.some((c) => c === normInput)) return 'correct';
+
+	const shortestLen = Math.min(...candidates.map((c) => c.length));
+	const threshold = Math.max(1, Math.floor(shortestLen * 0.2));
+	if (candidates.some((c) => levenshtein(normInput, c) <= threshold)) return 'close';
+
+	return 'wrong';
+}
+
+function levenshtein(a: string, b: string): number {
+	const m = a.length;
+	const n = b.length;
+	const row = Array.from({ length: n + 1 }, (_, j) => j);
+	for (let i = 1; i <= m; i++) {
+		let prev = row[0];
+		row[0] = i;
+		for (let j = 1; j <= n; j++) {
+			const tmp = row[j];
+			row[j] =
+				a[i - 1] === b[j - 1] ? prev : 1 + Math.min(prev, row[j], row[j - 1]);
+			prev = tmp;
+		}
+	}
+	return row[n];
+}