CreateEventPage's branding-default effect used a boolean ref guard that
locked in whichever theme_config arrived first. React Query can hand the
observer a cached (stale) copy on initial render and then push fresh data
once the network call resolves — the boolean ref meant the form kept the
stale theme and ignored the fresh one.
Replace the ref with a stringified-hash check: re-apply when the source
actually changes (including stale → fresh) but skip when nothing has.
User edits via the customizer aren't disturbed because settings.theme_config
only refreshes on a real Branding save, not on form state.
This unblocks the local pre-push smoke gate's 07-branding-default test,
which was test.fixme'd against this exact React Query staleness.
Paul Nothaft
401abf7a27