Add cached PrettyBlocks zone rendering and invalidation

[CySSoO]

Motivation

• Improve performance by caching final HTML output of PrettyBlocks zones keyed by zone + shop + lang + customer group.
• Reuse the existing EverblockCache helpers to store and retrieve rendered HTML.
• Ensure cache is invalidated when blocks or pages are changed so editors see updates immediately.

Description

• Added EverblockPrettyBlocks::renderZoneWithCache(string $zoneName, Context $context, Module $module): string that builds a cache key (zone, shop id, lang id, customer group), uses EverblockCache::cacheStore / EverblockCache::cacheRetrieve, and returns the rendered HTML. (file: src/Service/EverblockPrettyBlocks.php)
• Added EverblockPrettyBlocks::clearRenderCache() which delegates to EverblockCache::cacheDropByPattern using the new cache prefix. (file: src/Service/EverblockPrettyBlocks.php)
• Wired shortcode rendering to use the cached renderer by calling EverblockPrettyBlocks::renderZoneWithCache from EverblockTools::getPrettyblocksShortcodes. (file: src/Service/EverblockTools.php)
• Invalidate the render cache on persistent changes by calling EverblockPrettyBlocks::clearRenderCache() after an EverblockPage::save. (file: models/EverblockPage.php)
• Invalidate the render cache from admin operations that modify PrettyBlocks (add/update/delete/duplicate/bulk actions) by adding invalidation calls and detection logic in the PrettyBlocks admin controller. (file: controllers/admin/AdminEverBlockPrettyblockController.php)

Testing

• No automated tests were executed for this change.

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Codex Task