Publish blogpost about decomissioning the Slack bridge

[thibaultamartin]

Description

Add a post about the Foundation decommissioning its Slack bridge, and flag the bridge as obsolete

✔️ Checklist

• Keep this checklist
• Check for common mistakes:
  • Wrap plain URLs in <> to linkify them (learn more).
  • Use the right level of headings: The page title will use a level 1 headings, so your headings should use level 2 and below.
  • Use internal links: when linking to another page on https://matrix.org, use the Zola [label](@/target.md) syntax.
• For blog posts:
  • Verify the date and post ordering on the /blog page, especially for multiple posts on the same day. Prefer UTC format, e.g. 2025-12-01T14:00:00Z for Dec 1st, 2025, 2pm UTC.
  • Set the correct author and category. Browse existing ones at https://matrix.org/author/ and https://matrix.org/category/ to match them.
• If you hold a specific role in relation to the content you are contributing, such as project maintainer or on behalf of a team or organisation, please let us know. See example.
• If your PR is time-sensitive in any way, please mention the attached timeline and context in the PR description.
• Mention any issues related to the PR. Use GitHub keywords as appropriate.
• Your individual commits or pull request is signed off.

[cloudflare-workers-and-pages]

Deploying matrix-website with    Cloudflare Pages

Latest commit:	e81e8e6
Status:	✅  Deploy successful!
Preview URL:	https://ebb33aed.matrix-website.pages.dev
Branch Preview URL:	https://publish-slack-post.matrix-website.pages.dev

View logs

[HarHarLinks]

• let's also stop recommending it on the ecosystem page
• also obsolete the other mx-puppet bridge
• could use the chance to link to /homeserver as appropriate

[HarHarLinks]

(I would also like to see the info about the remaining bridges under /homeserver 😇)

[thibaultamartin]

let's also stop recommending it on the ecosystem page

@HarHarLinks I'm not sure where you mean?

[HarHarLinks]

let's also stop recommending it on the ecosystem page

@HarHarLinks I'm not sure where you mean?

- featured = true
+ featured = false

[MTRNord]

My issues were addressed so LGTM.

[HarHarLinks]

I've manually fixed #3021 here.

[HarHarLinks]

lgtm