chore(#1474): add reason= to remaining bare clippy allows outside dashboard

hive-c0re/src/lifecycle.rs

@@ -1128,7 +1128,11 @@ fn bind_child_agent_dirs(child: &str, binds: &mut Vec<BindMount>) {
     });
 }
 
-#[allow(clippy::too_many_lines)]
+#[allow(
+    clippy::too_many_lines,
+    reason = "one contiguous nspawn-flag assembly block; the length is the flag \
+              surface itself, splitting it would just hide the shape"
+)]
 async fn set_nspawn_flags(
     container: &str,
     runtime_dir: &Path,