fix(core): apply named function pattern to useEffect calls

[eunwoo-levi]

Overview

Apply the named function pattern to useEffect callbacks across multiple hooks to comply with the project's coding standards.

Summary

CLAUDE.md explicitly requires named functions in useEffect:

Named functions in useEffect — Improves stack traces and readability

useEffect(function handleResize() { ... }, []);  // ✅
useEffect(() => { ... }, []);                     // ❌

Changes

• usePreservedCallback — function syncCallbackRef()
• useInterval — function runImmediateCallback(), function startInterval()
• useDebounce — function cancelDebouncedOnUnmount()
• useDebouncedCallback — function clearDebouncedOnUnmount()
• useLoading — function trackMountedState()

Checklist

• Did you write the test code?
• Have you run yarn run fix to format and lint the code and docs?
• Have you run yarn run test:coverage to make sure there is no uncovered line?
• Did you write the JSDoc?