fix(xmpp): obfuscate client identity in protocol exchanges

Modify version responses to return a generic client name and omit
version strings. Drop the "profanity." prefix from dynamically
generated JID resources. Clear the XEP-0115 capabilities node URI to
prevent service discovery fingerprinting. These adjustments reduce the
client's attack surface by minimizing identifiable metadata.

src/xmpp/session.c

@@ -178,7 +178,7 @@ session_connect_with_details(const char* const jid, const char* const passwd, co
         saved_details.auth_policy = NULL;
     }
 
-    // use 'profanity' when no resourcepart in provided jid
+    // use random string when no resourcepart in provided jid
     auto_jid Jid* jidp = jid_create(jid);
     if (jidp->resourcepart == NULL) {
         auto_gchar gchar* resource = jid_random_resource();