fix(gqty): resolve crash and redundant fetches during prepareReactRender

[schettn]

Improve SSR stability and performance by ensuring valid GraphQL generation for null objects and deduplicating fetches for already-cached data.

• Update resolve.ts to fallback to leaf nodes or __typename for null objects and empty arrays, preventing invalid GraphQL queries (e.g., human { nullFather }).
• Update select.ts to return null instead of undefined for sub-paths of explicitly null nodes, correctly identifying resolved states.
• Implement a robust cache-aware filter in prepareRender.ts to skip redundant fetches for data already hydrated in the cache.
• Optimize cache notification and preparation checks with recursive hasValue and hasMissing helpers, replacing inefficient flat(Infinity) calls.
• Add comprehensive test cases in useQuery.test.tsx covering null object access and partial cache hits in arrays during SSR.

Note: @vicary All newly added test cases were verified to fail prior to these changes, confirming the identified bugs. While all existing tests continue to pass, please review the implementation for any unintended side effects or if an alternative architectural approach is preferred.

[schettn]

those are only whitespace changes.. sorry