[Security] harden client ID generation

[gonzaloriestra]

WHY are these changes introduced?

The ExtensionServerClient was using Math.random() to generate a client ID, which is not cryptographically secure and can lead to predictable IDs.

WHAT is this pull request doing?

Replaces Math.random() with a more secure ID generation method. Introduced a generateRandomId utility that uses globalThis.crypto.randomUUID() where available, falling back to the previous method if necessary to maintain compatibility across different environments.

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 4729937350354625746 started by @gonzaloriestra

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