[Security] Harden client ID generation in ExtensionServerClient

[gonzaloriestra]

WHY are these changes introduced?

The ExtensionServerClient was using Math.random() for ID generation, which is not cryptographically secure and can lead to predictable identifiers.

WHAT is this pull request doing?

This PR hardens the client ID generation by using globalThis.crypto.randomUUID() (CSPRNG) when available. It maintains a fallback to the original Math.random() logic for compatibility with environments that do not support the Web Crypto API.

How to test your changes?

CI

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

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PR created automatically by Jules for task 4903850465924769794 started by @gonzaloriestra

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