Revert "o1vm/pickles: remove unused ProverError constructors"

This reverts commit 96d42c1.

o1vm/src/pickles/prover.rs

@@ -34,6 +34,12 @@ use thiserror::Error;
 /// Errors that can arise when creating a proof
 #[derive(Error, Debug, Clone)]
 pub enum ProverError {
+    #[error("the proof could not be constructed: {0}")]
+    Generic(&'static str),
+
+    #[error("the provided constraint was not satisfied: {0}")]
+    ConstraintNotSatisfied(String),
+
     #[error("the provided constraint has degree {0} > allowed {1}; expr: {2}")]
     ConstraintDegreeTooHigh(u64, u64, String),
 }