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. Spoof the XEP-0115 capabilities node URI to
prevent service discovery/presence fingerprinting. These adjustments
reduce the client's attack surface by minimizing identifiable metadata.

src/xmpp/stanza.c

@@ -931,8 +931,8 @@ stanza_create_caps_query_element(xmpp_ctx_t* ctx)
 
     xmpp_stanza_t* identity = xmpp_stanza_new(ctx);
     xmpp_stanza_set_name(identity, "identity");
-    xmpp_stanza_set_attribute(identity, "category", "client");
     xmpp_stanza_set_type(identity, "pc");
+    xmpp_stanza_set_attribute(identity, "category", "client");
 
     ProfAccount* account = accounts_get_account(session_get_account_name());
     gchar* client = account->client;