Drain oversized LoRa packets to prevent RX FIFO corruption

src/lora_transport.cpp

@@ -138,6 +138,16 @@ bool lora_receive(LoraPacket &pkt, uint32_t timeout_ms) {
       while (LoRa.available() && len < sizeof(buffer)) {
         buffer[len++] = LoRa.read();
       }
+      if (LoRa.available()) {
+        while (LoRa.available()) {
+          LoRa.read();
+        }
+        if (SERIAL_DEBUG_MODE) {
+          Serial.println("rx_reject: oversize packet drained");
+        }
+        note_reject(RxRejectReason::LengthMismatch);
+        return false;
+      }
 
       if (len < 5) {
         note_reject(RxRejectReason::LengthMismatch);