c0re: schedule_prompt approval kind + worker + manager surface (#444 step 2)

hive-c0re/src/topology.rs

@@ -62,6 +62,32 @@ pub fn parent_of(name: &str) -> Option<String> {
     read().get(name).cloned().flatten()
 }
 
+/// True when `candidate` is `ancestor` or any descendant of
+/// `ancestor` per the current topology. Walks parents from
+/// `candidate` upward; the walk terminates at root or on a cycle
+/// (cycle defence: bounded to 32 hops, more than any plausible
+/// hive depth). Used by the cancel-authorization check in
+/// `manager_server::handle_cancel_schedule` to enforce
+/// "managers can cancel anything their subtree owns."
+#[must_use]
+pub fn is_descendant_of(candidate: &str, ancestor: &str) -> bool {
+    if candidate == ancestor {
+        return true;
+    }
+    let topo = read();
+    let mut cur = candidate.to_owned();
+    for _ in 0..32 {
+        let Some(parent) = topo.get(&cur).cloned().flatten() else {
+            return false;
+        };
+        if parent == ancestor {
+            return true;
+        }
+        cur = parent;
+    }
+    false
+}
+
 /// Persist the topology map. Sorted JSON output (BTreeMap is sorted by
 /// key) keeps git diffs minimal across re-writes. Best-effort —
 /// returns an `io::Error` so callers can decide whether a failure