Feature: Seamless Cross-Preset Communication via UDP Multicast Bridging (#7753)

* Added compatibility between nodes on different Presets through `Mesh via UDP`

* Optimize multicast handling and channel mapping

- FloodingRouter: remove redundant UDP-encrypted rebroadcast suppression.
- Router: guard multicast fallback with HAS_UDP_MULTICAST and map fallback-decoded packets
  to the local default channel via isDefaultChannel()
- UdpMulticastHandler: set transport_mechanism only after successful decode

* trunk fmt

* Move setting transport mechanism.

---------

Co-authored-by: GUVWAF <thijs@havinga.eu>

src/mesh/Channels.h

@@ -94,6 +94,8 @@ class Channels
 
     bool ensureLicensedOperation();
 
+    bool setDefaultPresetCryptoForHash(ChannelHash channelHash);
+
   private:
     /** Given a channel index, change to use the crypto key specified by that index
      *