feat(targeted): add targeted practice functionality

feat(analytics); add analytics page

src/types/test.ts

@@ -0,0 +1,11 @@
+// types/exam.ts
+export type ExamMode = "MODULE" | "TARGETED" | "SIMULATION" | "DRILLS";
+
+export interface StartExamPayload {
+  sheet_id: string;
+  topic_ids: string[];
+  difficulty: "EASY" | "MEDIUM" | "HARD";
+  question_count: number;
+  time_limit_minutes: number;
+  mode: ExamMode;
+}