Scheduled/automatic sync for 'Update Recent Modified Stock' (Shopify integration)

Title: Scheduled/automatic sync for 'Update Recent Modified Stock' (Shopify integration)

Body:

Currently, stock changes made in Cin7 Omni (adjustments, stocktakes, credit note/return approvals, etc.) only reach Shopify in two ways: when a Shopify order is downloaded, or when someone manually runs 'Update Recent Modified Stock'. There's no option to have that function run automatically on a schedule.

In practice, this means any stock change that isn't tied to a Shopify order — a stocktake correction, a sample/PR send-out, a warehouse adjustment — sits unsynced in Cin7 indefinitely until someone remembers to manually trigger the update, or until an unrelated Shopify order happens to pull a fresh sync. With multiple staff making adjustments throughout the day, that's not something we can reliably rely on a person to catch every time.

The result: Shopify keeps showing stock as available that no longer physically exists, and it gets sold — oversold orders, refunds, and unhappy customers.

Requested feature: allow 'Update Recent Modified Stock' to be scheduled to run automatically at a set interval (e.g. every 15–30 minutes), rather than only on manual trigger or Shopify order download. Support advised that continuous real-time syncing would be too heavy on processing, but 'Update Recent Modified Stock' is already designed as a lightweight delta/incremental push (only mapped products changed since the last run) — so a scheduled version of that same function, rather than a fully real-time sync, should avoid the performance concern while closing this gap.

Happy to provide more detail — this was raised via support ticket #327175 if useful for context.