feat: add publish time validation in parse_price_feed_updates_internal

- Add validation to check if publish times are within [min_allowed_publish_time, max_allowed_publish_time] range
- Return PythReceiverError::PriceFeedNotFoundWithinRange (error code 16) when publish times are outside allowed range
- Fix type casting from u64 to i64 for proper comparison with price_feed_message.publish_time

Co-Authored-By: [email protected] <[email protected]>

Author: devin-ai-integration[bot]

target_chains/stylus/contracts/pyth-receiver/src/lib.rs

@@ -382,8 +382,15 @@ impl PythReceiver {
 
                     match msg {
                         Message::PriceFeedMessage(price_feed_message) => {
+                            let publish_time = price_feed_message.publish_time;
+                            
+                            if (min_allowed_publish_time > 0 && publish_time < min_allowed_publish_time as i64) ||
+                               (max_allowed_publish_time > 0 && publish_time > max_allowed_publish_time as i64) {
+                                return Err(PythReceiverError::PriceFeedNotFoundWithinRange);
+                            }
+                            
                             let price_info_return = (
-                                U64::from(price_feed_message.publish_time),
+                                U64::from(publish_time),
                                 I32::from_be_bytes(price_feed_message.exponent.to_be_bytes()),
                                 I64::from_be_bytes(price_feed_message.price.to_be_bytes()),
                                 U64::from(price_feed_message.conf),