Fix timezone conversion for stepped cron expressions

[egknight]

Summary

• Expand stepped cron hour fields before applying timezone offsets.
• Preserve the existing carry-aware grouping when converted values cross midnight.
• Add coverage for everyFourHours() during British Summer Time and update the existing stepped-hour cases.

Background

schedule:list currently passes stepped fields such as */4 and 1-23/2 through timezone conversion unchanged. This changes the real execution times when the event timezone differs from the display timezone.

For example, 0 */4 * * * in Europe/London during British Summer Time should be represented in UTC as:

0 23 * * *
0 3,7,11,15,19 * * *

Instead, it is currently returned as 0 */4 * * *. Consumers of the JSON schedule can therefore invoke the scheduler at the wrong UTC hours, after which Laravel's timezone-aware due check rejects the event.

This change expands supported numeric step syntax into explicit values before passing those values through the converter's existing offset and carry logic. Plain numeric fields retain their current behavior, while unsupported cron syntax continues to pass through unchanged.

Tests

• vendor/bin/phpunit tests/Integration/Console/Scheduling/ScheduleListCommandTest.php
• vendor/bin/pint src/Illuminate/Console/Scheduling/CronExpressionTimezoneConverter.php tests/Integration/Console/Scheduling/ScheduleListCommandTest.php

[xiCO2k]

Hey @egknight we did this PR covering a bit more edge cases: #60877

can you take a look if works for your case?

Thanks.