feat(keyring-sdk): add new entropy support

[ccharly]

Temporarily add the new entropy support in our keyring-sdk package.

We might re-consider this choice and put that somewhere else, but for now that will do.

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Note

Medium Risk
Touches cryptographic fingerprinting of wallet entropy; algorithm or ID format changes would break stable identifiers across clients, though scope is additive and well-tested with golden vectors.

Overview
Adds entropy source modeling to @metamask/keyring-sdk: exported types (Entropy, EntropyId, EntropyType, category/implementation unions) and helpers to derive stable identifiers without exposing raw secrets.

fingerprint and toEntropyFingerprint use HMAC-SHA256 over entropy bytes with the fixed message metamask:fingerprint (UUID v4 from the first 16 digest bytes, or full hex for auditing). toEntropyId builds IDs as entropy:{category}:{implementation}:{uuid}, using that fingerprint when material is available or _ when it is omitted (e.g. hardware wallets). APIs are async for future Web Crypto compatibility.

Also adds @noble/hashes, re-exports the module from the package entry, documents the feature in the changelog, and covers behavior with unit tests including golden vectors.

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