feat: add MyExams, MyResults, Settings, and Workspace components

- Implemented MyExams component for managing user exams, including loading, deleting, and creating new exams.
- Created MyResults component to display user results with options to review and delete results.
- Developed Settings component for updating user display name and changing password.
- Introduced Workspace component to serve as a container for MyExams, MyResults, and Settings, with navigation between tabs.

frontend/src/utils/validation.ts

@@ -13,4 +13,14 @@ export const validateExam = (data: unknown): string | null => {
   return null
 }
 
-export const parseExam = (data: unknown): Exam => data as Exam
+function generateId(): string {
+  return Math.random().toString(36).slice(2, 10)
+}
+
+export const parseExam = (data: unknown): Exam => {
+  const exam = data as Exam
+  if (!exam.id) {
+    exam.id = generateId()
+  }
+  return exam
+}