Validate size and offset in recordings playback requests

[acebear17]

Summary

In this pull request, the following changes are made:

• In the recordings websocket 'get' handler, check that size and ptr are non-negative integers and cap size at 1MB.
• Wrap the buffer/read block in try/catch, like the other websocket handlers.
• Skip sending if fs.read returns an error.

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• 🧠 I used LLMs/AI in this contribution and reviewed all generated content.
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• 🤖 I added or updated automated tests where appropriate.
• 📄 Documentation updates are included (if applicable).
• 🧰 Dependency updates are listed and explained.
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