refactor: optimize hash table iterations and fix security issues #58

- refactor(core): replace g_hash_table_get_keys with g_hash_table_iter_init
  * Eliminates temporary GList allocations
  * Improves iteration performance
  * Affected: connection.c, cmd_defs.c, cmd_funcs.c, omemo.c, gpg.c,
    disco.c, form.c, autocompleters.c, capabilities.c, callbacks.c

- fix(xmpp): correct queued_messages loop in connection.c:1031
  * Remove incorrect NULL check that prevented message storage
  * calloc zeros array, causing loop to skip immediately
  * Fixes dropped messages during reconnection with SM enabled

- fix(ui): prevent format string vulnerabilities in cons_show calls
  * Replace cons_show(variable) with cons_show("%s", variable)
  * Protects against format string attacks if variables contain %
  * Updated instances across cmd_funcs.c, connection.c, ox.c,
    console.c, core.c

src/command/cmd_defs.c

@@ -2825,16 +2825,15 @@ cmd_search_index_any(char* term)
     int terms_len = g_strv_length(processed_terms);
 
     for (int i = 0; i < terms_len; i++) {
-        GList* index_keys = g_hash_table_get_keys(search_index);
-        GList* curr = index_keys;
-        while (curr) {
-            char* index_entry = g_hash_table_lookup(search_index, curr->data);
+        GHashTableIter iter;
+        gpointer key, value;
+        g_hash_table_iter_init(&iter, search_index);
+        while (g_hash_table_iter_next(&iter, &key, &value)) {
+            char* index_entry = (char*)value;
             if (g_str_match_string(processed_terms[i], index_entry, FALSE)) {
-                results = g_list_append(results, curr->data);
+                results = g_list_append(results, key);
             }
-            curr = g_list_next(curr);
         }
-        g_list_free(index_keys);
     }
 
     return results;
@@ -2848,13 +2847,14 @@ cmd_search_index_all(char* term)
     auto_gcharv gchar** terms = g_str_tokenize_and_fold(term, NULL, NULL);
     int terms_len = g_strv_length(terms);
 
-    GList* commands = g_hash_table_get_keys(search_index);
-    GList* curr = commands;
-    while (curr) {
-        char* command = curr->data;
+    GHashTableIter iter;
+    gpointer key, value;
+    g_hash_table_iter_init(&iter, search_index);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        char* command = (char*)key;
+        char* command_index = (char*)value;
         int matches = 0;
         for (int i = 0; i < terms_len; i++) {
-            char* command_index = g_hash_table_lookup(search_index, command);
             if (g_str_match_string(terms[i], command_index, FALSE)) {
                 matches++;
             }
@@ -2862,11 +2862,8 @@ cmd_search_index_all(char* term)
         if (matches == terms_len) {
             results = g_list_append(results, command);
         }
-        curr = g_list_next(curr);
     }
 
-    g_list_free(commands);
-
     return results;
 }