feat: Add SHA-256 utility

[FrederikBolding]

We have a bunch of SHA-256 utilities scattered in different repos, this attempts to upstream a stable one that uses the faster native option when possible.

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Note

Adds a sha256 utility that prefers Web Crypto and falls back to @noble/hashes, with tests and public export.

• Utilities
  • Add sha256(bytes: Uint8Array) in src/hashing.ts using globalThis.crypto.subtle.digest('SHA-256') when available, falling back to @noble/hashes/sha256.
• Tests
  • New src/hashing.test.ts verifying digests, fallback behavior when crypto.subtle/digest are unavailable, and Node 18 webcrypto setup.
• Exports
  • Re-export sha256 from src/index.ts; update snapshots in src/index.test.ts and src/node.test.ts to include "sha256".

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[Mrtenz]

Missing export in index.ts