🐛 Bug: Sponsors page references outdated twitter.com URL instead of x.com

Describe the bug

The sponsors page (/overview/sponsors) contains a hardcoded link to
twitter.com/jsonschema in the "Thank you" tweet benefit description.
While it redirects, the source code should reference the correct and
current platform URL x.com/jsonschema to reflect the platform rebrand
from Twitter to X.

Steps To Reproduce

1. Visit https://json-schema.org/overview/sponsors
2. Inspect the "Thank you" tweet benefit under Bronze sponsors
3. Hover over the @jsonschema link — it shows twitter.com/jsonschema

Expected Behavior

The link should point to:
https://x.com/jsonschema

Current behavior

The link in the sponsor benefits section points to:
https://twitter.com/jsonschema

Additional context

The rest of the site (footer, community page) already correctly uses
x.com links. This is an inconsistency in the source code that should
be updated for accuracy and consistency.

Screenshots

Device Information [optional]

- OS:MacOS
- Browser:Chrome
- version:

Are you working on this issue?

Yes

Do you think this work might require an [Architectural Decision Record (ADR)]? (significant or noteworthy)

Yes

Start by opening the source for the /overview/sponsors page and locating the Bronze sponsors “Thank you” tweet benefit. Verify the rendered @jsonschema link and compare it with the site's existing footer and community links; done means the sponsor link uses https://x.com/jsonschema and the page remains correct.