refactor(zcash): rename redacted PCZT signing helper

diff --git a/rust/apps/zcash/src/lib.rs b/rust/apps/zcash/src/lib.rs
index 5858263..4475028 100644
--- a/rust/apps/zcash/src/lib.rs
+++ b/rust/apps/zcash/src/lib.rs
@@ -722,7 +722,7 @@ fn sign_checked_pczt_with_policy<P: consensus::Parameters>(
     if policy == ShieldedActionPolicy::Batch && signable_actions.is_empty() {
         return Err(ZcashError::PcztNoMyInputs);
     }
-    let signed = pczt::sign::sign_pczt_to_pczt(pczt, seed)?;
+    let signed = pczt::sign::sign_and_redact_pczt(pczt, seed)?;
     let signed = if signable_actions.is_empty() {
         signed
     } else {
diff --git a/rust/apps/zcash/src/pczt/sign.rs b/rust/apps/zcash/src/pczt/sign.rs
index 3913733..e9b4ad0 100644
--- a/rust/apps/zcash/src/pczt/sign.rs
+++ b/rust/apps/zcash/src/pczt/sign.rs
@@ -242,10 +242,10 @@ impl PcztSigner for SeedSigner<'_> {
 
 /// Signs `pczt` and serializes the stamped, redacted response.
 ///
-/// Thin wrapper over `sign_pczt_to_pczt`; see it for the full contract.
+/// Thin wrapper over `sign_and_redact_pczt`; see it for the full contract.
 #[cfg(feature = "cypherpunk")]
 pub fn sign_pczt(pczt: Pczt, seed: &[u8]) -> crate::Result<Vec<u8>> {
-    sign_pczt_to_pczt(pczt, seed)?
+    sign_and_redact_pczt(pczt, seed)?
         .serialize()
         .map_err(|e| ZcashError::SigningError(format!("serialize signed PCZT: {e:?}")))
 }
@@ -254,7 +254,7 @@ pub fn sign_pczt(pczt: Pczt, seed: &[u8]) -> crate::Result<Vec<u8>> {
 /// so callers that still need the parsed value (in-memory post-sign
 /// verification) avoid a byte round trip.
 #[cfg(feature = "cypherpunk")]
-pub fn sign_pczt_to_pczt(pczt: Pczt, seed: &[u8]) -> crate::Result<Pczt> {
+pub fn sign_and_redact_pczt(pczt: Pczt, seed: &[u8]) -> crate::Result<Pczt> {
     super::validate_supported_pczt(&pczt)?;
 
     let seed_fingerprint =