Feat/style and publish front matter summary in article

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Description

This PR changes how a front matter summary added by a user is handled. As of now, most of the articles don't have proper summaries that introduce their contents. This feature will hopefully help us raise more interest among developers in creating nice summaries.

First off, this is an example of a good summary that quickly provides clues about the contents and helps the reader to decide in a matter of seconds if they should read it.

Back to the summary creation, Hugo offers three ways to add summaries:

• Front matter summary -- this PR changes how it is handled
• Manual summary -- nothing changed
• Automatic summary -- nothing changed

To create a front matter summary, you need to add the following to your article's front matter:

title: 'My article'
date: ...
summary: 'This is a front matter summary.'

In addition to the standard behavior of showing the summary on a list page, this PR also placed it at the beginning of an article in a different formatting style (link to a preview).

This is how a front matter summary looks in a list page:

This is how the proposed summary looks in an article:

Related

• This feature can also indirectly help us deal with issue List page having blank cards in the article card array #166 . Front matter summaries will be written in plain text, and articles with such summaries will show up correctly on list pages.

Testing

Tested locally.

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

[FBEZ]

I completely support this change. Not only because it's a standard (both in academic settings and elsewhere) but also because it forces to author to reflect on the overall goal of their article. Dealing the summary/abstract through the front matter makes it sense and it's the most "structured" way to deal with it.