fix: carry numeric round/floor/ceil precision >= 60s into minute/hour/day

A numeric $precision passed to round()/floor()/ceil() is always resolved
to the "second" unit. Once the precision reaches or exceeds 60 (e.g.
round(3600) meaning "nearest hour"), the rounding stayed confined to the
second field (range 0-59) and never carried into minute/hour/day, unlike
the equivalent string form (round('hour')).

Re-target the unit to minute/hour/day once the numeric precision reaches
that unit's own span in seconds, rescaling the precision accordingly,
mirroring the existing week -> day re-targeting already in roundUnit().
Sub-minute numeric precisions are unaffected.

src/Carbon/Traits/Rounding.php

@@ -70,6 +70,24 @@ trait Rounding
 
         $precision *= $factor;
 
+        // A numeric precision is in seconds, so once it spans the next coarser
+        // unit it must be re-targeted there, like "week" -> "day" above.
+        if ($normalizedUnit === 'second' && (\is_int($precision) || \is_float($precision))) {
+            $secondsPerHour = static::MINUTES_PER_HOUR * static::SECONDS_PER_MINUTE;
+            $secondsPerDay = static::HOURS_PER_DAY * $secondsPerHour;
+
+            if ($precision >= $secondsPerDay) {
+                $normalizedUnit = 'day';
+                $precision /= $secondsPerDay;
+            } elseif ($precision >= $secondsPerHour) {
+                $normalizedUnit = 'hour';
+                $precision /= $secondsPerHour;
+            } elseif ($precision >= static::SECONDS_PER_MINUTE) {
+                $normalizedUnit = 'minute';
+                $precision /= static::SECONDS_PER_MINUTE;
+            }
+        }
+
         if (!isset($ranges[$normalizedUnit])) {
             throw new UnknownUnitException($unit);
         }