feat(api): add review day handling and dynamic campaign length

apps/api/src/srs.test.ts

@@ -134,6 +134,8 @@ describe("the plan", () => {
       expect(isRestDay(date)).toBe(false);
       if (day.gate) expect(weekdayOf(date)).toBe(6);
       if (day.topics) expect(weekdayOf(date)).toBeLessThan(6);
+      // Reviews run Mon/Tue and Thu/Fri; Wednesday and the weekend stay free.
+      if (day.review) expect([1, 2, 4, 5]).toContain(weekdayOf(date));
     }
   });
 
@@ -150,6 +152,20 @@ describe("the plan", () => {
     expect(topicDate(999)).toBeUndefined();
   });
 
+  test("a review is booked once, and no problem sits in two reviews", () => {
+    const issues = new Set<number>();
+    const problems = new Set<number>();
+    for (const day of Object.values(SCHEDULE)) {
+      if (!day.review) continue;
+      expect(issues.has(day.review.issue)).toBe(false);
+      issues.add(day.review.issue);
+      for (const lc of day.review.problems) {
+        expect(problems.has(lc)).toBe(false);
+        problems.add(lc);
+      }
+    }
+  });
+
   test("every gate and set problem is reserved from the samplers", () => {
     for (const day of Object.values(SCHEDULE)) {
       for (const lc of [...(day.gate ?? []), ...(day.problems ?? [])]) {