[BUG]: Unhandled SSL/TLS failure in Wikipedia augmentation causes 500 on /get_mcq

### Bug Description

While testing PDF input (~11 questions) with "Use Wikipedia" enabled, I encountered an SSL EOF error originating from the MediaWiki API call.
- The exception propagates up the request path and results in a 500 response from `/get_mcq` .Hence leading to unending request and failures .

## Current Behavior

- External MediaWiki SSL failure is not handled
- Entire request fails
- No graceful fallback
- User receives generic 500

## Expected Behavior

If Wikipedia augmentation fails:
- Log warning
- Continue quiz generation without Wikipedia enrichment
- Return structured success response
- Optionally notify user enrichment was skipped

### Steps to Reproduce

1. Upload a larger PDF (tested with ~10–11 questions)
2. Enable "Use Wikipedia"
3. Submit request
4. Backend returns 500 with SSLError (EOF occurred in violation of protocol)

### Logs and Screenshots

```
(Caused by SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:2427)')))
127.0.0.1 - - [12/Feb/2026 23:44:09] "POST /get_mcq HTTP/1.1" 500 -
```

### 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