Function generateAutoFilename

generateAutoFilename(prefix: string, ext?: string): string
Generate a timestamped filename using a fixed prefix (no user input).

Useful for auto-generated files like AI chat logs, poll results, and Q&A session exports.
Parameters
- prefix: string
  A short, lowercase identifier (e.g. 'ai_chat', 'polls').
- ext: string = '.json'
  File extension including the dot (default '.json').
Returns string
A filename like ai_chat_2026-04-03_14-30-45.json.
Example
```
generateAutoFilename('polls')
// 'polls_2026-04-03_14-30-45.json'

generateAutoFilename('ai_chat')
// 'ai_chat_2026-04-03_14-30-45.json'
```
- Defined in packages/utilities/src/filenames.ts:86