Resolve #3606260 "Recurring smart date"

Kieran Cottrequested to merge
issue/smart_date-3606260:3606260-recurring-smart-date into 4.2.x

Fixes recurring Smart Date fields on nested entities such as Paragraphs.

The widget now stores recurrence rules against the entity type and bundle that actually host the field, rather than assuming the root form entity is the host. Parent entity lookup now tries entityQuery() first and only falls back to a direct field table lookup when the rrule column cannot be resolved.

Also fixes recurrence month-limit handling for rule entities and avoids data loss when no instances are generated within the configured window.

Closes #3606260

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