Release 2026.9.28

Legal holds (#70): a hold on people, groups, domains, tenants or the
whole server keeps everything it covers from being destroyed, by anyone,
until it's released; deleted accounts keep their data. Audit records
name accounts by their full address and holds by their case name. The
daily clean-up of expired archived items works again.

Prepared Explain answers relabeled for this release; no setting changed
since 2026.9.27.2, so all 706 carry over.

crates/types/src/branding.rs

@@ -81,7 +81,7 @@ fn legacy_setting(name: &str, is_set: impl Fn(&str) -> bool) -> Option<String> {
 #[macro_export]
 macro_rules! brand_version {
     () => {
-        "2026.9.27.2"
+        "2026.9.28"
     };
 }