[BUG][HIGH PRIORITY]: Output page crashes with Cannot read properties of undefined (reading forEach)

### Bug Description

The Output page crashes at runtime with:

`TypeError: Cannot read properties of undefined (reading 'forEach')`

This happens when stored payload keys are missing or malformed, and the page assumes arrays always exist before iterating.

Affected page:
- [eduaid_web/src/pages/Output.jsx](eduaid_web/src/pages/Output.jsx)

## Why this is high priority

- It breaks the core quiz result flow on the web UI.
- Users see a blank/error overlay instead of generated questions.
- It is reproducible and user-facing.

## Current behavior

The page calls `forEach` on values that may be undefined, such as:
- `output`
- `output_mcq.questions`
- `output_boolq.Boolean_Questions`

When any of these keys are absent, React crashes in the effect hook.

## Expected behavior

The Output page should:
1. Safely parse local storage data.
2. Treat missing arrays as empty arrays.
3. Render without crashing even if payload shape is partial.

### Steps to Reproduce

1. Generate questions with a payload shape that does not include all expected keys.
2. Open the Output page.
3. Observe runtime crash: `Cannot read properties of undefined (reading 'forEach')`.

### Environment Details

_No response_

### Impact

High - Major feature is broken

### Code of Conduct

- [x] I have joined the [Discord server](https://discord.gg/hjUhu33uAn) and will post updates there
- [x] I have searched existing issues to avoid duplicates