actions: deny plants annotated denied/<id> tag

apply-commit denials now leave a git object behind: tag
denied/<id> annotated with the operator's note (or empty body
if they didn't supply one) at proposal/<id> inside the applied
repo. rejected configs become first-class git history — git
show denied/<id> in the manager's applied.git mount yields the
tree the operator rejected plus the reason. helper event
carries the tag for parity with deployed/failed. spawn denials
fall through unannotated since they have no proposal commit.
deny becomes async (single git plumbing call); dashboard +
admin-socket callers grow .await.

hive-c0re/src/server.rs

@@ -146,7 +146,7 @@ async fn dispatch(req: &HostRequest, coord: Arc<Coordinator>) -> HostResponse {
                 HostResponse::success()
             }
             HostRequest::Deny { id } => {
-                actions::deny(&coord, *id, None)?;
+                actions::deny(&coord, *id, None).await?;
                 HostResponse::success()
             }
         })