job_queue: finish reparent call-site swap, delete dead sync path

hive-c0re/src/job_queue/model.rs

@@ -196,12 +196,6 @@ pub enum NodeKind {
     /// window. `(child, new_parent)` pairs, applied in order under one
     /// `META_LOCK` acquisition / one git commit (`meta::bulk_commit_topology`
     /// handles both the single- and multi-move case uniformly).
-    #[allow(
-        dead_code,
-        reason = "constructed by templates::reparent(), landed ahead of the call-site swap \
-                   (pending an answer on whether that swap should be synchronous or \
-                   fire-and-forget) — exercised today by job_queue::tests only"
-    )]
     Reparent {
         moves: Vec<(hive_types::Ident, Option<hive_types::Ident>)>,
     },