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

hive-priv/src/main.rs

@@ -155,7 +155,11 @@ async fn write_line_event(writer: &mut OwnedWriteHalf, stream: PrivStream, data:
 /// For streaming ops (`CreateContainer`/`UpdateContainer` with `stream: true`)
 /// output lines are forwarded to `writer` as `PrivEvent::Line` messages and
 /// the returned strings are empty.
-#[allow(clippy::too_many_lines)]
+#[allow(
+    clippy::too_many_lines,
+    reason = "flat dispatch table: one match arm per privileged request variant; \
+              splitting it would scatter the routing logic"
+)]
 async fn exec(req: PrivRequest, writer: &mut OwnedWriteHalf) -> Result<(String, String)> {
     match req {
         PrivRequest::StartContainer { ref name } => {