Address GUVWAF feedback: count short-RX as rxGood + promote invalid-protobuf to WARN

GUVWAF flagged two remaining log/counter items on the hardened RX path:

- RadioLibInterface.cpp: the short-packet branch was neither rxGood nor
  rxBad after the previous revision. Move rxGood++ above the
  payloadLen<0 check so every CRC-passed OTA reception counts regardless
  of subsequent header-validation outcome.
- Router.cpp: 'Invalid protobufs in received mesh packet (bad psk?)' is
  more than DEBUG-worthy — either our channel key is wrong or someone's
  feeding us corrupted data. Promote to LOG_WARN per GUVWAF's request.

("Invalid portnum" at the same site stays at LOG_DEBUG — that one only
means the decoded protobuf had the default portnum field, which is a
weaker signal.)

Author: nightjoker7

src/mesh/RadioLibInterface.cpp

@@ -505,11 +505,15 @@ void RadioLibInterface::handleReceiveInterrupt()
         // Skip the 4 headers that are at the beginning of the rxBuf
         int32_t payloadLen = length - sizeof(PacketHeader);
 
+        // CRC-good OTA reception — count as rxGood regardless of whether we process
+        // it further. Short/from==0/pool-exhausted packets still represent successful
+        // airtime usage and shouldn't silently vanish from the stats.
+        rxGood++;
+
         // check for short packets
         if (payloadLen < 0) {
             LOG_WARN("Ignore received packet too short");
         } else {
-            rxGood++;
             // altered packet with "from == 0" can do Remote Node Administration without permission.
             // Still counted as a "good" OTA reception above — we just refuse to process it.
             if (radioBuffer.header.from == 0) {

src/mesh/Router.cpp

@@ -499,7 +499,7 @@ DecodeState perhapsDecode(meshtastic_MeshPacket *p)
                 meshtastic_Data decodedtmp;
                 memset(&decodedtmp, 0, sizeof(decodedtmp));
                 if (!pb_decode_from_bytes(bytes, rawSize, &meshtastic_Data_msg, &decodedtmp)) {
-                    LOG_DEBUG("Invalid protobufs in received mesh packet id=0x%08x (bad psk?)", p->id);
+                    LOG_WARN("Invalid protobufs in received mesh packet id=0x%08x (bad psk?)", p->id);
                 } else if (decodedtmp.portnum == meshtastic_PortNum_UNKNOWN_APP) {
                     LOG_DEBUG("Invalid portnum (bad psk?)");
 #if !(MESHTASTIC_EXCLUDE_PKI)