fix(security): prevent CWE-134 format string injection

- add "%s" to unsafe cons_show/log_*/win_println calls
- add check-cwe134.sh static analysis script
- integrate security check into CI pipeline

Closes #85

src/ui/console.c

@@ -938,7 +938,7 @@ cons_show_account_list(gchar** accounts)
                 theme_item_t presence_colour = theme_main_presence_attrs(string_from_resource_presence(presence));
                 win_println(console, presence_colour, "-", "%s", accounts[i]);
             } else {
-                cons_show(accounts[i]);
+                cons_show("%s", accounts[i]);
             }
         }
         cons_show("");