Performance Issue: Unnecessary Re-renders of QuestionCard (Memo) Due to Prop Instability

## Summary
The `QuestionCard (Memo)` component is experiencing persistent and unnecessary re-rendering, nullifying the intended memoization benefits and leading to significant performance costs, especially in math-heavy chat sessions.

## Details
### 1. The Core Issue
- `QuestionCard (Memo)` consistently shows high render duration (1.3ms–1.7ms) in profiler results across many commits and state changes.
- Its `React.memo` wrapper is being bypassed: the component is re-rendering even when it theoretically should not.

### 2. Root Cause: Upstream State and Prop Instability
- Most re-renders are triggered by the parent `ChatInterface` component propagating updates downstream.
- Likely cause: Unstable function/object/array props originating from parent state or inline declarations, causing identity changes on every render and breaking memoization.

### 3. Additional Impact
- Heavy child components such as `MathRenderer` and `MathComponent` (with up to 3ms additional cost) amplify the impact of every unnecessary `QuestionCard` render.
- Other memoized chat components (`ChatInput`, `ChatMessages`) show similar instability, suggesting wider architectural prop-stability problems.

## Evidence
Refer to the attached profiler screenshot for concrete rendering duration and frequency details.

## Recommendation
- Audit all props passed to `QuestionCard`: ensure objects, arrays, and functions are memoized/stable across renders unless their values truly change.
- Refactor `ChatInterface` (and other parent components) to avoid inline prop creation and to leverage `useMemo`/`useCallback` where appropriate.
- Examine how similar issues affect other memoized components in the chat interface.

---
**Root cause and evidence:**
- Unstable props from `ChatInterface` -> `QuestionCard (Memo)` (and similar memo components).
- High, repeating render durations on profiler output ([see attached image](image1)).

---
**Environment:** Commit range 1–15, visible in profiler timeline.