Reassurance prettyblock: optional slider with per-device settings

[CySSoO]

Motivation

• Allow the Reassurance prettyblock repeaters to be displayed as an optional slider instead of a static grid.
• Give administrators control to enable the slider on desktop, mobile or both and to set different items-per-slide counts for desktop and mobile.

Description

• Added new block configuration fields in src/Service/EverblockPrettyBlocks.php: slider, slider_devices, slider_items_desktop, and slider_items_mobile.
• Updated the template views/templates/hook/prettyblocks/prettyblock_reassurance.tpl to conditionally render grid or slider layouts, add ever-slick-carousel classes and emit data-items-desktop/data-items-mobile attributes used by the carousel.
• Enhanced views/js/everblock.js to read data-items-desktop and data-items-mobile and build Slick responsive settings so desktop/mobile slide counts can be applied independently.
• Changes implement conditional desktop/mobile rendering (separate markup/CSS classes) so the slider can be restricted to one device type or enabled on both.

Testing

• No automated tests were executed for this change.

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Codex Task