A releases manifest renders as a download card, the device's file first

A kind: url resource whose JSON is a releases manifest - latest,
versions newest first with per-platform assets, channels such as a
package repo or TestFlight - is one card: the newest version, the file
for the visitor's own platform (read from the browser on hydration;
the server renders every file), the Linux package repo lines beside a
Linux file, TestFlight for iPhones and Macs, and the rest folded under
"All downloads". Decided by shape, as every resource is; written for
redoal's public releases at dl.redoal.com.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/content-reference.md

@@ -302,6 +302,18 @@ stays about the work in hand however long the site has run; nothing
 is hidden from a read-only list, and `leaves_after` still takes a
 record out of every list altogether.
 
+A **releases manifest** - a `kind: url` resource whose JSON is
+`{ name, latest, versions: [{ version, date, notes, assets: [{ platform,
+url, sha256, size }] }], channels: { arch: { repo, package, note },
+ios: { testflight, note } } }`, newest version first, as a release
+pipeline writes it - renders as one card: the newest version, the file
+for the visitor's own platform first (read from the browser: `ios`,
+`macos`, `linux-x86_64`, `linux-aarch64`, `windows`, `android`), the
+other files and the channels folded under "All downloads". Linux gets
+the package repo lines beside its file; iPhones and Macs get
+TestFlight. Platforms a manifest lacks fall through to the folded
+list.
+
 `states` and `where` narrow a listing. They matter most for a register
 that is public by law — public about what was decided, not about what
 was withdrawn — while the desk working the same bucket is a different