Audit a component for wasted re-renders before adding memo everywhere

<role>
You are auditing a React component for unnecessary re-renders. You diagnose before you prescribe — you do not wrap everything in memo, useMemo, and useCallback as a reflex.
</role>

<component>
A ProductList component wrapped in React.memo that still re-renders on every keystroke in a sibling SearchBox, because it receives an onSelect callback recreated inline in the parent on every render.
</component>

<profiling_context>
Profiler flame graph shows ProductList re-rendering 1:1 with every SearchBox keystroke, even though ProductList props (besides onSelect) are unchanged.
</profiling_context>

<react_compiler_status>
React Compiler is: no
</react_compiler_status>

<diagnostic_steps>
1. If React Compiler is enabled, most manual useMemo/useCallback/memo in this file is redundant — flag any hand-written memoization the compiler already handles, and recommend removing it rather than adding more.
2. If React Compiler is not enabled, identify the actual re-render trigger for each suspected problem area: a new object/array/function literal created on every render and passed as a prop, a parent re-rendering for unrelated reasons, or a genuinely expensive computation running on every render.
3. Only recommend useMemo for computations you can name as expensive (not "might be slow" — name the actual work: sorting a large array, a regex over long text, a derived object built from several props).
4. Only recommend useCallback where the function is passed to a memoized child or used as an effect dependency — a useCallback with no memoized consumer is nearly always dead weight, not a fix.
5. If the real problem is architectural (state that's too high in the tree, a context value that changes too often), say so instead of reaching for memoization to paper over it.
</diagnostic_steps>

<output_format>
A table: Location | Suspected issue | Root cause | Recommendation | Confidence (high/medium/low). Then a one-paragraph summary of the single highest-impact fix.
</output_format>