GLib's GMutex is a raw futex, so ThreadSanitizer cannot see the
happens-before edge g_main_context_invoke_full provides and fails the
thread lane on plane_render_executor_test. Publish the completion
payload through an explicit release/acquire pair, and suppress the
remaining reports that originate wholly inside libglib's own source
bookkeeping. Races on repository memory still fail the run; verified
0/100 failing TSan runs in an ubuntu:24.04 container (20/20 before).