Views date filter breaks input with an explicit timezone offset

Note: Issue and my MRs are created with the help of AI, reviewed and checked by me.

Problem/Motivation

Smart Date replaces core's Views date filter (smart_date_views_plugins_filter_alter()). Its Date::getMinAndMax() parses the value with new DateTimePlus($value, $site_timezone). When the value carries its own offset (2026-10-12T15:23:23Z, @1791818603, …+05:00), PHP keeps that offset. The code then reads year, month, day, hour, minute and second from the object and rebuilds the timestamp with createFromArray(…, $site_timezone). So the wall-clock time of the input's zone is reinterpreted as site time, and the filter value moves by the difference of the two offsets.

Core's Date filter (strtotime()) handles the same input correctly. Smart Date 4.0.x did too, at granularity "second"; the shift came with the getMinAndMax() refactor in #3410547.

This hits every exposed or contextual date filter that receives machine input: feeds and APIs with a changed_since / from parameter in UTC or as a unix timestamp. For > the filter returns up to one or two hours of extra items. For < it drops items.

Steps to reproduce

1. Site timezone Europe/Vienna, Smart Date 4.2.x or 4.3.x enabled.
2. A view on nodes with an exposed changed filter, operator >=, granularity "second".
3. Pass 2026-10-12T15:23:23Z, the same moment as @1791818603 or 2026-10-12T17:23:23+02:00.

Proposed resolution

In getMinAndMax(), convert the parsed dates to the site timezone before the components are read:

Remaining tasks

• MR against 4.3.x with the fix and the test.

User interface changes

None.

API changes

None.

Data model changes

None.