fix(review): avoid review effort boundary undercounts

src/review/review-effort.ts

@@ -46,9 +46,10 @@ function bandForEffort(effort: number): 1 | 2 | 3 | 4 | 5 {
   return 5;
 }
 
-/** Map a persisted minutes estimate back to its complexity band (inverse of `estimateReviewEffort`'s minutes step). */
+/** Map a persisted rounded minutes estimate to the highest complexity band it could represent. */
 export function bandFromMinutes(minutes: number): 1 | 2 | 3 | 4 | 5 {
-  return bandForEffort(Math.max(0, minutes) / MINUTES_PER_EFFORT);
+  const maxRepresentedEffort = (Math.max(0, minutes) + 0.5) / MINUTES_PER_EFFORT;
+  return bandForEffort(maxRepresentedEffort);
 }
 
 /** Estimate the review effort of a change set. Pure and deterministic. */

test/unit/review-effort.test.ts

@@ -69,4 +69,11 @@ describe("bandFromMinutes (#2155)", () => {
       expect(bandFromMinutes(sample.minutes)).toBe(sample.band);
     }
   });
+
+  it("keeps rounded boundary minutes in the higher possible band (regression for #2155)", () => {
+    expect(bandFromMinutes(5)).toBe(2);
+    expect(bandFromMinutes(20)).toBe(3);
+    expect(bandFromMinutes(60)).toBe(4);
+    expect(bandFromMinutes(150)).toBe(5);
+  });
 });

test/unit/stats.test.ts

@@ -152,6 +152,10 @@ describe("aggregateReviewEffort — maintainer complexity fold (#2155)", () => {
     // minutes 4 -> band 1; minutes 96 -> band 4 -> rounded avg 3; total 100.
     expect(aggregateReviewEffort([4, 96])).toEqual({ avgBand: 3, totalEstimatedMinutes: 100 });
   });
+
+  it("keeps boundary-rounded minutes in the higher possible avgBand (regression for #2155)", () => {
+    expect(aggregateReviewEffort([5, 20, 60, 150])).toEqual({ avgBand: 4, totalEstimatedMinutes: 235 });
+  });
 });
 
 describe("computeStats — review-effort read is fail-safe", () => {