Sign plaintext packets in licensed mode (#10969)

* feat: sign licensed plaintext packets

Preserve and publish identity keys in licensed mode so existing XEdDSA signatures can authenticate plaintext traffic. Sign licensed broadcasts and direct messages when they fit, while keeping PKI encryption disabled and normal routing behavior unchanged.

* fix(security): persist licensed channel sanitation

* fix(security): close licensed migration lifecycle gaps

* fix(security): address licensed signing review feedback

* test: restore signing globals from Unity teardown

* fix(baseui): allow confirmed ham region selection

* fix(baseui): guard region picker validation

* style: trunk fmt

---------

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>
Co-authored-by: Austin <vidplace7@gmail.com>

src/modules/NodeInfoModule.cpp

@@ -169,14 +169,8 @@ meshtastic_MeshPacket *NodeInfoModule::allocReply()
         ignoreRequest = true;
         return NULL;
     } else {
-        ignoreRequest = false;     // Don't ignore requests anymore
-        meshtastic_User u = owner; // deliberate copy: the licensed strip below must not clobber the global owner state
-
-        // Strip the public key if the user is licensed
-        if (u.is_licensed && u.public_key.size > 0) {
-            memset(u.public_key.bytes, 0, sizeof(u.public_key.bytes));
-            u.public_key.size = 0;
-        }
+        ignoreRequest = false; // Don't ignore requests anymore
+        meshtastic_User u = owner;
 
         // FIXME: Clear the user.id field since it should be derived from node number on the receiving end
         // u.id[0] = '\0';