Image Optimization: Add Lazy Loading Support

[arunshenoy99]

Proposed changes

Story: https://jira.newfold.com/browse/PRESS7-76

• Adds a new setting to enable lazy loading for images under the Image Optimization tab.
• Implements a two-layer approach:
  1. Backend:
     • Adds the loading="lazy" attribute to images and avatars directly in the generated HTML.
  2. Frontend:
     • A JavaScript listener applies the loading="lazy" attribute to dynamically added elements in the DOM.

Type of Change

Production

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update
• Refactoring / housekeeping (changes to files not directly related to functionality)

Development

• Tests
• Dependency update
• Environment update / refactoring
• Documentation Update

Video

lazy-loading.mp4

Checklist

• I have read the CONTRIBUTING doc
• I have viewed my change in a web-browser
• Linting and tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[arunshenoy99]

Just merging this PR into its base branch. I’ll put together a combined PR for all the Image Optimization changes so we can see the full picture and make reviewing easier.