fix: Prevent PhotoSwipe script from wrapping already linked images

[saasan]

Description

This PR fixes the issue where the PhotoSwipe script wraps images that are already inside <a> tags, causing the original link functionality to be lost.

Related Issue

Fixes #187

Problem

The PhotoSwipe script in _includes/extensions/photo-swipe.html currently wraps all <img> elements (except those with emoji class) in a new <a class="photo-swipe"> element. This includes images that are already wrapped in links, breaking their original functionality.

Before (buggy behavior):

<!-- Original markup -->
<a href="https://example.com">
  <img src="image.jpg">
</a>

<!-- After PhotoSwipe processing -->
<a href="https://example.com">
  <a class="photo-swipe" href="image.jpg" ...>
    <img src="image.jpg">
  </a>
</a>

The original link to https://example.com becomes inaccessible.

Solution

Added a check to skip images whose parent element is already an <a> tag, preserving their original link behavior.

After this fix:

<!-- Images already in links are preserved -->
<a href="https://example.com">
  <img src="image.jpg">
</a>

<!-- Standalone images still get PhotoSwipe functionality -->
<a class="photo-swipe" href="standalone.jpg" ...>
  <img src="standalone.jpg">
</a>

Changes

• Added condition el.parentElement?.tagName.toLowerCase() === "a" to skip images that are already inside anchor tags
• Preserves original link functionality for linked images
• Maintains PhotoSwipe functionality for standalone images

Testing

• ✅ Linked images maintain their original links and don't trigger PhotoSwipe
• ✅ Standalone images still get PhotoSwipe functionality
• ✅ Images with emoji class continue to be ignored as before
• ✅ No breaking changes to existing PhotoSwipe behavior

Files Changed

• _includes/extensions/photo-swipe.html