[FSSDK-12294] hook fix

[junaed-optimizely]

Summary

• Implement stale-while-error pattern across all hooks: when a store-level error occurs (e.g., CDN datafile fetch failure) but a valid config and user context already exist, hooks now return the existing decision/userContext alongside the error instead of nulling them out. Previously, if onReady() rejected after a sync datafile was already loaded, all hooks immediately returned { decision: null, error } — discarding a perfectly usable datafile. This was overly aggressive for the common case where a sync datafile is provided and a background CDN refresh fails due to network issues.

Test plan

Tests have been added to address the change.

Issues

• FSSDK-12294

[Copilot]

Pull request overview

This PR updates the Optimizely React hooks to implement a stale-while-error pattern so that store-level errors don’t discard already-available userContext/decisions.

Changes:

• Update sync hooks to return existing decisions/userContext alongside store errors when config + user context are available.
• Update async decision state machine to surface store errors while still executing decisions when possible.
• Add/adjust tests to validate stale-with-error behavior across hooks.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/hooks/types.ts	Expands result unions to allow returning stale decisions alongside an Error.
src/hooks/useOptimizelyUserContext.ts	Returns existing userContext even when state.error is set.
src/hooks/useOptimizelyUserContext.spec.tsx	Adds test coverage for stale user context returned with store error.
src/hooks/useDecide.ts	Returns decision even when store error exists (stale-while-error).
src/hooks/useDecide.spec.tsx	Adds test for stale decision returned with store error.
src/hooks/useDecideAll.ts	Returns all decisions even when store error exists (stale-while-error).
src/hooks/useDecideAll.spec.tsx	Adds test for stale decisions returned with store error.
src/hooks/useDecideForKeys.ts	Returns decisions-for-keys even when store error exists (stale-while-error).
src/hooks/useDecideForKeys.spec.tsx	Adds test for stale decisions returned with store error.
src/hooks/useAsyncDecision.ts	Adjusts async decision flow to keep executing when config + userContext exist, and propagate store error on resolve.
src/hooks/useDecideAsync.spec.tsx	Adds test for stale decision returned with store error in async hook.
src/hooks/useDecideAllAsync.spec.tsx	Adds test for stale decisions returned with store error in async hook.
src/hooks/useDecideForKeysAsync.spec.tsx	Adds test for stale decisions returned with store error in async hook.

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