feat(dips): log proposal rejections at INFO level

When an RCA proposal is rejected, log the rejection reason, error, and
deployment ID (when decodable) at INFO level. Previously the rejection
was returned via the gRPC response with no server-side log at INFO,
making debugging difficult without access to the client.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: MoonBoi9001

crates/dips/src/lib.rs

@@ -350,6 +350,17 @@ fn bytes32_to_ipfs_hash(bytes: &[u8; 32]) -> String {
     bs58::encode(&multihash).into_string()
 }
 
+/// Try to extract the deployment ID from raw signed RCA bytes.
+///
+/// Best-effort: returns `None` if any decoding step fails.
+pub(crate) fn try_extract_deployment_id(rca_bytes: &[u8]) -> Option<String> {
+    let signed_rca = SignedRecurringCollectionAgreement::abi_decode(rca_bytes).ok()?;
+    let metadata =
+        AcceptIndexingAgreementMetadata::abi_decode(signed_rca.agreement.metadata.as_ref())
+            .ok()?;
+    Some(bytes32_to_ipfs_hash(&metadata.subgraphDeploymentId.0))
+}
+
 /// Validate and create a RecurringCollectionAgreement.
 ///
 /// Performs validation:

crates/dips/src/server.rs

@@ -152,6 +152,7 @@ impl IndexerDipsService for DipsServer {
 
         // Validate and store RCA
         let domain = crate::rca_eip712_domain(self.chain_id, self.recurring_collector);
+        let deployment_id = crate::try_extract_deployment_id(&signed_voucher);
         match crate::validate_and_create_rca(
             self.ctx.clone(),
             &domain,
@@ -169,7 +170,12 @@ impl IndexerDipsService for DipsServer {
             }
             Err(e) => {
                 let reject_reason = reject_reason_from_error(&e);
-                tracing::warn!(error = %e, reason = ?reject_reason, "RCA rejected");
+                tracing::info!(
+                    error = %e,
+                    reason = ?reject_reason,
+                    deployment_id = deployment_id.as_deref().unwrap_or("unknown"),
+                    "RCA proposal rejected"
+                );
                 Ok(Response::new(SubmitAgreementProposalResponse {
                     response: ProposalResponse::Reject.into(),
                     reject_reason: reject_reason.into(),