Publish multipart resume on four

[scriptogre]

Publishes the merged hx-multipart resume fix from #3915 on the four branch.

The documented jsDelivr URL reads and minifies src/ext/hx-multipart.js directly from four, so this makes the fix available without a new htmx release.

Also lists Django and FastHTML support in scriptogre/multipart-response.

This does not change the htmx version, package metadata, or dist.

Checks:

• Add multipart resume cursors #3915 CI passed before merge
• Content checks pass
• Diff contains only multipart source, tests, and docs