🧹 Fix 'any' types in useQuiz.ts

[RMantis]

🎯 What: Replaced the any type for forceKana in nextQuestion and related variables (currentKanaRef, nextKana, unlockedItemToForce, pool) with appropriate strict types (KanaItem, WordItem, or union types).
💡 Why: To improve code maintainability and strictness by resolving ambiguous any usages and adhering to TypeScript best practices. This ensures compile-time checks accurately represent the data flowing through the hook.
✅ Verification: Verified changes by running npm run lint which passed successfully (the Unexpected any errors are fixed) and npm run build which succeeded, indicating no regressions in project compilation. Code review confirmed changes are safe and correct.
✨ Result: Improved codebase health and readability without changing application behavior.

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PR created automatically by Jules for task 2899153043881562222 started by @RMantis

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