Prep work for better Store and Forward (#8999)

* make channels.h getHash public

* router.* make the encrypted packet copy available for modules to access

* Update src/mesh/Router.h

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Set p_encrypted to nullptr after release

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/mesh/Router.h

@@ -91,6 +91,9 @@ class Router : protected concurrency::OSThread, protected PacketHistory
         before us */
     uint32_t rxDupe = 0, txRelayCanceled = 0;
 
+    // pointer to the encrypted packet
+    meshtastic_MeshPacket *p_encrypted = nullptr;
+
   protected:
     friend class RoutingModule;