fix(ui,db): harden NULL handling, fix CWE-134, optimize iterations

security(CWE-134): fix format string injections + add CI check
fix(ui): subwindow lifecycle, newwin/newpad guards, fallback timestamps
fix(db): sqlite cleanup on failures, sqlite3_close_v2
fix(xmpp): queued_messages loop, barejid leak
perf(core): g_hash_table_iter_init instead of g_hash_table_get_keys
refactor(ui): CLAMP macro in _check_subwin_width
test: XEP-0012 and XEP-0045 functional tests

Author: jabber.developer2
Closes #58, #85

src/xmpp/form.c

@@ -437,18 +437,7 @@ form_get_form_type_field(DataForm* form)
 gboolean
 form_tag_exists(DataForm* form, const char* const tag)
 {
-    GList* tags = g_hash_table_get_keys(form->tag_to_var);
-    GList* curr = tags;
-    while (curr) {
-        if (g_strcmp0(curr->data, tag) == 0) {
-            g_list_free(tags);
-            return TRUE;
-        }
-        curr = g_list_next(curr);
-    }
-
-    g_list_free(tags);
-    return FALSE;
+    return g_hash_table_contains(form->tag_to_var, tag);
 }
 
 form_field_type_t