Update GetSignatureFormat to return formatted message with example values

Co-Authored-By: Chris Li <chris.li.2046@gmail.com>

Author: devin-ai-integration[bot]

aggregator/auth.go

@@ -187,7 +187,14 @@ func (r *RpcServer) verifyOperator(ctx context.Context, operatorAddr string) (bo
 }
 
 func (r *RpcServer) GetSignatureFormat(ctx context.Context, req *avsproto.GetSignatureFormatReq) (*avsproto.GetSignatureFormatResp, error) {
+	chainId := int64(1) // Example Ethereum mainnet
+	issuedAt := time.Now().UTC().Format("2006-01-02T15:04:05.000Z")
+	expiredAt := time.Now().Add(time.Hour * 24).UTC().Format("2006-01-02T15:04:05.000Z")
+	walletAddress := "0x0000000000000000000000000000000000000000" // Example address
+	
+	formattedMessage := fmt.Sprintf(authTemplate, chainId, issuedAt, expiredAt, walletAddress)
+	
 	return &avsproto.GetSignatureFormatResp{
-		Format: authTemplate,
+		Format: formattedMessage,
 	}, nil
 }