(fix): broken connections

codec/src/data_value.rs

@@ -289,7 +289,7 @@ impl DataValue {
     pub fn as_number(&self) -> Option<i128> {
         match self {
             DataValue::SignedNumber(n) => Some(*n),
-            DataValue::UnsignedNumber(n) => Some(*n as i128),
+            DataValue::UnsignedNumber(n) => i128::try_from(*n).ok(),
             _ => None,
         }
     }
@@ -1232,6 +1232,18 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn unsigned_number_conversion_rejects_i128_overflow() {
+        assert_eq!(
+            DataValue::UnsignedNumber(i128::MAX as u128).as_number(),
+            Some(i128::MAX)
+        );
+        assert_eq!(
+            DataValue::UnsignedNumber(i128::MAX as u128 + 1).as_number(),
+            None
+        );
+    }
+
     #[test]
     fn test_empty_container_and_array_have_distinct_framing() {
         let container = DataValue::Container(vec![])