fix(timer): carry rounded minutes into the hour in humanDuration

src/timer.mjs

@@ -45,8 +45,12 @@ export function parseDuration(text) {
 export function humanDuration(seconds) {
   const total = Math.max(0, Math.round(Number(seconds) || 0));
   if (total < 60) return `${total}s`;
-  const h = Math.floor(total / 3600);
-  const m = Math.round((total % 3600) / 60);
+  // Round to whole minutes first, then split — computing hours and minutes off
+  // the raw seconds lets a remainder that rounds up to 60 (59m30s..59m59s) print
+  // as "60m"/"1h 60m" instead of carrying into the hour it belongs in.
+  const minutes = Math.round(total / 60);
+  const h = Math.floor(minutes / 60);
+  const m = minutes % 60;
   if (!h) return `${m}m`;
   return m ? `${h}h ${m}m` : `${h}h`;
 }

test/timer.test.mjs

@@ -42,6 +42,13 @@ test("a duration is written short, and stays exact enough", () => {
   assert.equal(humanDuration(5400), "1h 30m");
   assert.equal(humanDuration(7200), "2h");
   assert.equal(humanDuration(0), "0s");
+  // A sub-hour remainder that rounds up to 60 minutes carries into the hour,
+  // rather than printing "60m" or "1h 60m".
+  assert.equal(humanDuration(3599), "1h");
+  assert.equal(humanDuration(3570), "1h");
+  assert.equal(humanDuration(3569), "59m");
+  assert.equal(humanDuration(7199), "2h");
+  assert.equal(humanDuration(86399), "24h");
 });
 
 test("on writes an active timer and off turns it into an entry", async (t) => {