v0.0.3 - Runtime Hasher and C ABI Streaming

Third public release of zig-files-hash, focused on chunked/streaming hashing.

Highlights

• Added public runtime hasher API in Zig:
  • RuntimeHasher.init(alg, options)
  • RuntimeHasher.update(chunk)
  • RuntimeHasher.digestLength()
  • RuntimeHasher.final(out)
  • RuntimeHasher.finalResult() + digest.slice() helper flow
• dispatch now uses RuntimeHasher as the shared hashing path.
• Kept public helper digestLength(alg) for non-streaming consumers.
• Added test coverage for RuntimeHasher.digestLength.

C ABI v2

• ABI version bumped: ZFH_API_VERSION = 2.
• Streaming C ABI now uses caller-provided state buffer (inplace, no heap allocations).
• Added streaming C functions:
  • zfh_hasher_state_size
  • zfh_hasher_state_align
  • zfh_hasher_init_inplace
  • zfh_hasher_update
  • zfh_hasher_final
• zfh_digest_length now resolves via Zig public digestLength(alg) to keep one
  source of truth for digest sizes.
• Added C ABI streaming tests (chunked success, key-required mapping,
  buffer-too-small on final, invalid state checks).
• Defined post-final behavior for streaming state:
  repeated zfh_hasher_final and zfh_hasher_update after final return
  ZFH_INVALID_ARGUMENT.

Compatibility notes

• Zig API remains allocation-free:
  • stringHash / fileHash unchanged for existing usage
  • streaming is additive via RuntimeHasher
• C API consumers should regenerate bindings against
  src/zig_files_hash_c_api.h (ZFH_API_VERSION = 2).
• Minimum Zig version remains 0.15.2.