fix: wrap month start/interval across year (#692)

[arimu1]

Summary

Fixes #692

ExecutionTime only returned the starting month for expressions like 10/3 (e.g. only October each year), skipping the rest of the every-N-months sequence (Jan/Apr/Jul).

Cause

EveryFieldValueGenerator for On(start)/period set from = start and to = field end. For months that yields only values ≥ start that fit in 1–12, so 10/3 → {10} only.

Fix

For the MONTH field with start/period (On + period), treat the progression as continuous across the year boundary using modular match:

floorMod(month - start, period) == 0

So 10/3 → {1, 4, 7, 10} (Oct, Jan, Apr, Jul). Other fields (hours, minutes, …) keep non-wrapping behavior (22/3 remains {22}).

Reproduction (now fixed)

CronParser parser = new CronParser(CronDefinitionBuilder.instanceDefinitionFor(CronType.QUARTZ));
ExecutionTime et = ExecutionTime.forCron(parser.parse("0 0 0 15 10/3 ? *"));

et.nextExecution(ZonedDateTime.parse("2026-01-01T00:00:00Z"));
// → 2026-01-15 (was 2026-10-15)

et.getExecutionDates(
    ZonedDateTime.parse("2025-10-01T00:00:00Z"),
    ZonedDateTime.parse("2026-10-31T00:00:00Z"));
// → Oct 15 2025, Jan 15 2026, Apr 15 2026, Jul 15 2026, Oct 15 2026

Test plan

• Issue692Test — next/last/getExecutionDates + sequence for 10/3
• EveryFieldValueGeneratorTest — month wrap candidates; hours 22/3 still non-wrapping
• Full suite: 810 tests, 0 failures (Temurin 21)