feat: add formatting, storage, and validation utilities

frontend/src/utils/validation.ts

@@ -0,0 +1,16 @@
+import type { Exam } from '../types'
+
+export const validateExam = (data: unknown): string | null => {
+  if (!data || typeof data !== 'object') return 'Not a JSON object'
+  const d = data as Record<string, unknown>
+  if (!d['title']) return 'Missing "title"'
+  if (!Array.isArray(d['questions']) || d['questions'].length === 0) return 'Missing "questions" array'
+  for (const q of d['questions'] as Record<string, unknown>[]) {
+    if (!q['id']) return 'Question missing id'
+    if (!q['type']) return `Question "${String(q['id'])}" missing type`
+    if (!q['prompt']) return `Question "${String(q['id'])}" missing prompt`
+  }
+  return null
+}
+
+export const parseExam = (data: unknown): Exam => data as Exam