v0.4

Added

• Zstd.versionNumber() — the linked zstd version as a single integer
  (MAJOR * 10000 + MINOR * 100 + PATCH, e.g. 10507 for 1.5.7), for
  programmatic version checks alongside version().

Changed

• ZstdSkippableContent is now a true immutable value: it defensively copies its
  bytes on the way in and out, and compares by content
  (equals / hashCode / toString over the payload, not array identity).
• Public methods fail fast with a named NullPointerException on null byte[],
  dictionary, or sample arguments, instead of an opaque failure deep in native
  code. Streams are documented as not thread-safe; digested dictionaries
  (ZstdCompressDict / ZstdDecompressDict) as immutable and safe to share.

Fixed

• A streaming wrapper that failed partway through construction (e.g. an invalid
  parameter or dictionary) leaked the native context. The context is now freed
  on every constructor error path.

Security

• The bundled library is extracted into a directory created owner-only
  (rwx------) atomically at creation, not just by default. The third-party
  setup-zig CI action is pinned to a full commit SHA.