chore: justify the remaining keep-only cast + serde-default allows with reasons

hive-bash-mcp/src/bin/mcp.rs

@@ -168,7 +168,10 @@ struct BashRunArgs {
     wait_seconds: Option<u64>,
 }
 
-#[allow(clippy::unnecessary_wraps)]
+#[allow(
+    clippy::unnecessary_wraps,
+    reason = "serde `#[serde(default = ...)]` requires the default fn's return type to match the field's `Option<u64>`, so the `Some` wrap is mandatory even though the value is constant"
+)]
 fn default_wait() -> Option<u64> {
     Some(3)
 }