Add Discord integration

[captainark]

Hi!

I've added a Discord Integration to Miniflux, which generated those kind of messages on new entries:

This PR was hacked together from other integrations and trial and error. I'm more than open to feedback if anything needs cleaning up.

I believe this PR would close #1642 if merged.

Do you follow the guidelines?

• I have tested my changes
• There are no breaking changes
• I really tested my changes and there is no regression
• Ideally, my commit messages follow the Conventional Commits specification
• I read this document: https://miniflux.app/faq.html#pull-request

[fguillot]

I'm getting a 400 response when doing a quick test.

After adding some debugging, Discord reply this response body: {"embeds": ["0"]}

And Miniflux sent this request body:

{
  "embeds": [
    {
      "title": "Feed update from Miniflux",
      "color": 5793266,
      "fields": [
        {
          "name": "Updated RSS feed",
          "value": "Le Monde.fr - Actualités et Infos en France et dans le monde"
        },
        {
          "name": "Link to article",
          "value": "[Incendies à Los Angeles : artistes et collectionneurs font l'inventaire des œuvres d'art carbonisées](https://www.lemonde.fr/culture/article/2025/01/12/incendies-a-los-angeles-artistes-et-collectionneurs-font-l-inventaire-des-uvres-carbonisees_6494694_3246.html)"
        },
        {
          "name": "Author",
          "inline": true
        },
        {
          "name": "Source website",
          "value": "https://www.lemonde.fr/",
          "inline": true
        }
      ]
    }
  ]
}

Looks like the value field must be present. The "authors" section should not be sent if the feed does not contains any author.

[captainark]

I "fixed" the issue when the authors section isn't defined in the RSS feed.

Here's what it looks like with my latest commit: