feat: add pagination to search results

[KKamJi98]

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (refactoring and improving code)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Description

• mirror the home page paginator UI in the search panel so users can browse search results page by page
• cache raw SimpleJekyllSearch output and render only the active page, keeping the DOM small and the behavior consistent on desktop/mobile (including ellipsis + prev/next arrows)
• expose search.limit and search.per_page in _config.yml so site owners can control how many hits are fetched and shown per page
• lock sass-embedded to 1.77.5 so CI uses the precompiled build instead of compiling 1.93.3 (which fails during the dart-sass rename step)
• added regression coverage by running bash tools/test.sh

Additional context

• Fixes Make search result limit configurable #2583
• re-tested locally after pinning the gem; GitHub Actions build (3.1) should now succeed