Lift important notes to top of changelog

Author: devonh

CHANGES.md

@@ -1,5 +1,19 @@
 # Synapse 1.144.0 (2025-12-09)
 
+## Deprecation of MacOS Python wheels
+
+The team has decided to deprecate and stop publishing python wheels for MacOS.
+Synapse docker images will continue to work on MacOS, as will building Synapse
+from source (though note this requires a Rust compiler).
+
+## Unstable mutual rooms endpoint is now behind an experimental feature flag
+
+Admins using the unstable [MSC2666](https://github.com/matrix-org/matrix-spec-proposals/pull/2666) endpoint (`/_matrix/client/unstable/uk.half-shot.msc2666/user/mutual_rooms`),
+please check [the relevant section in the upgrade notes](https://github.com/element-hq/synapse/blob/develop/docs/upgrade.md#upgrading-to-v11440) as this release contains changes
+that disable that endpoint by default.
+
+
+
 No significant changes since 1.144.0rc1.