Feat/improve cover image gen

What does this PR change? What problem does it solve?

This pull request introduces improvements to the cover image generation in the Hugo PaperMod theme. The changes include:

Refactoring: cover.html has been refactored to use the
element for image captions, enhancing HTML5 semantics and accessibility.
Bug Fixes: Removed pointer-event prevention from entry-cover images to ensure better user interaction.
Code Quality: Added comments and managed whitespace for better code readability.

Was the change discussed in an issue or in the Discussions before?

No.

PR Checklist

[ ] This change adds/updates translations and I have used the template present here.
[ ] I have enabled maintainer edits for this PR.
[ ] I have verified that the code works as described/as intended.
[ ] This change adds a Social Icon which has a permissive license to use it.
[x] This change does not include any CDN resources/links.
[x] This change does not include any unrelated scripts such as bash and python scripts.
[ ] This change updates the overridden internal templates from HUGO's repository.