CryptoHasher: match Bun binary input and HMAC key semantics

Scope

Port Bun CryptoHasher input normalization and keyed digest behavior into the native corpus runtime without fixture rewrites or delegated Bun execution.

The complete js/bun/util corpus currently reaches 852 passes and first fails in js/bun/util/bun-cryptohasher.test.ts at HMAC sha1 with a String key. The harness accepts the string but stores plain byte arrays; the digest path later feeds an Array slice to TextDecoder, whose native contract requires an ArrayBuffer or view.

Required parity

• Normalize string, Buffer, ArrayBuffer, SharedArrayBuffer, ArrayBufferView, and Blob inputs into stable byte views with Bun-compatible offsets/lengths.
• Preserve Bun.file rejection behavior.
• Match keyed HMAC vectors, copy/digest lifecycle, algorithm aliases, encodings, and post-digest errors.
• Keep all upstream corpus files unchanged.

Acceptance

• packages/runtime/test/bun-corpus/js/bun/util/bun-cryptohasher.test.ts passes in the native Home runner.
• Neighboring hash/crypto and full js/bun/util tranches have no regressions.
• Commit and test evidence are linked back to #66.

Completed in 37215a5 (fix(runtime): implement native CryptoHasher HMAC).

Implemented real keyed BoringSSL HMAC for Bun and Node crypto shims; added real BLAKE2s, SHAKE, MD4, RIPEMD-160, SHA-512/224, SHA-512/256, and md5-sha1 digest routing; normalized binary inputs; removed both fixed HMAC vector tables and the fixture-specific shortcut; matched the Bun sha128 alias and keyed BLAKE2s/SHAKE rejection; and made the native bridge GC-safe by filling a caller-owned output view.

Validation:

• bun-cryptohasher.test.ts: 397 pass / 0 fail
• hash.test.js: 20 / 20
• crypto.hmac.test.ts: 74 / 74
• crypto-hmac-algorithm.test.ts: 5 / 5
• mixed 16,000-call native digest stress probe: pass
• arbitrary HMAC keys/messages match pinned Bun byte-for-byte
• full js/bun/util: 1,249 pass / 23 fail / 1 unsupported / 2 TODO, up from 852 pass / 24 fail; the first remaining failure is unrelated

The broader js/node/crypto/crypto.test.ts now passes its hash assertions and reaches the separate SHA-224 signing gap.