Progress on the MainPod circuit (#159)

* feat: add SignedPodVerify test

* unify circuits style

* more clear sizes

* get operation_verify test working

* be consistent with names

src/frontend/mod.rs

@@ -1091,6 +1091,7 @@ pub mod tests {
             max_operation_args: 5,
             max_custom_predicate_arity: 5,
             max_custom_batch_size: 5,
+            ..Default::default()
         };
 
         let mut alice = MockSigner { pk: "Alice".into() };