v1.74.1

Fixed

• A user-property write during an onboarding no longer blanks the app.
  OnboardingDataGate followed the user-property store reactively: a
  setUserProperty mid-flow changed the merged audience params, the React Query
  key followed them, the query answered data: undefined for the never-seen key,
  and the gate rendered null — unmounting the entire subtree under the
  provider (in hosts that wrap the app: router reset, every screen's state lost),
  refetching get-onboarding-steps, and remounting. The only workaround was to
  seed every property before the provider mounted.

  The rule now is: audience resolution happens at serve time, and a served
  payload is frozen for that presentation. OnboardingProvider resolves the
  effective params once, from the first ready snapshot of the store, and
  pins them for the lifetime of the mount (useAudienceParams); the data gate
  just fetches what it is handed. A property written during the flow — or a change to
  the customAudienceParams prop — does not re-key, refetch or swap the
  onboarding; it applies to the next serve (next mount, next launch). Hosts
  can write a property the moment they compute it, even mid-onboarding. The
  corollary: anything the current serve must target on has to be set before
  the provider mounts. reset() likewise clears for the next serve.

  PaywallProvider is deliberately unchanged: a paywall is served at
  register(moment), so it is right that its catalog follows the store until
  then, and it never blanks while refetching.

  The escape hatch is intact: client.clearCache() plus invalidating
  ["onboardingQuestions", …] still refetches — the same query, under the pinned
  audience, without an unmount. Re-targeting with the current properties is a
  new serve: remount the provider — at a flow boundary, since a remount is the
  full teardown.

• useOnboardingStep / useOnboardingStart now build the query the gate
  served. They built their own useSuspenseQuery from the raw
  customAudienceParams prop, while the gate (since 1.74.0) merged the store over
  it — so with a non-empty store the two keys differed: a second fetch, resolved
  without the user's properties, and that was the payload the screens
  rendered. OnboardingProvider now resolves the params once and hands that
  same value to both the data gate and the OnboardingProgressContext the hooks
  already read, so both build the same query and there is exactly one fetch.
  The hooks themselves are unchanged.

Changed

• Tests — the headless package can now render React in tests (react-dom +
  jsdom dev dependencies, *.test.tsx excluded from tsc). The provider suite
  renders the real OnboardingProvider against a fake client.

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