feat(landing): заглушка страницы с рабочей формой

apps/landing/src/lib/sendLead.ts

@@ -0,0 +1,27 @@
+// Отправка заявки на POST /api/lead.
+import type { FieldErrors, LeadRequest, LeadResponse } from '@kvarta/shared/lead';
+
+export type SubmitOutcome =
+  | { kind: 'success' }
+  | { kind: 'invalid'; fieldErrors: FieldErrors }
+  | { kind: 'failed' };
+
+export type SendLead = (body: LeadRequest) => Promise<SubmitOutcome>;
+
+export const sendLead: SendLead = async (body) => {
+  try {
+    const res = await fetch('/api/lead', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(body),
+    });
+    const data = (await res.json().catch(() => null)) as LeadResponse | null;
+    if (res.ok && data?.ok) return { kind: 'success' };
+    if (res.status === 400 && data && !data.ok && data.error === 'validation') {
+      return { kind: 'invalid', fieldErrors: data.fieldErrors };
+    }
+    return { kind: 'failed' };
+  } catch {
+    return { kind: 'failed' };
+  }
+};