v0.6

Added

• ZstdCompressCtx.refPrefix(MemorySegment) / ZstdDecompressCtx.refPrefix(...)
  — reference native content as a single-use prefix (raw-content dictionary) for
  the next frame only: the building block for delta compression (compress a new
  version against a similar previous one). The prefix is referenced, not copied
  or digested, and writes no dictionary ID; the decompressor must reference the
  same prefix to decode. Binds ZSTD_CCtx_refPrefix / ZSTD_DCtx_refPrefix.
  Segment-only by design — heap callers that need a copy should use
  loadDictionary instead.
• Zstd.dictId(byte[]) / Zstd.dictId(MemorySegment) — read the dictionary id
  stamped in raw dictionary bytes without wrapping them in a ZstdDictionary.
  Binds ZSTD_getDictID_fromDict.
• ZstdDictionaryId value type — a record wrapping the 32-bit dictionary id
  with an unsigned value(), isPresent(), and the NONE sentinel for "no id".
• ZstdFrame.decompressedSize(byte[]) / ZstdFrame.decompressedSize(MemorySegment)
  — the exact combined decompressed size of all concatenated frames, summed from
  each frame header (throws if any frame does not record its size). Complements
  decompressedBound (upper bound). Binds ZSTD_findDecompressedSize.
• ZstdFrame.headerSize(byte[]) / ZstdFrame.headerSize(MemorySegment) — the size
  of a frame's header computed from just its leading bytes (as few as 5), without a
  full parse. Binds ZSTD_frameHeaderSize.
• ZstdFrame.decompressionMargin(byte[]) / ZstdFrame.decompressionMargin(MemorySegment)
  — the extra room needed to decompress a frame in place (output buffer overlaps
  the compressed input at its tail), sized decompressedSize + margin. Binds
  ZSTD_decompressionMargin.
• ZstdDictionary.compressDict(int) / compressDict() / decompressDict() —
  factories for digested dictionaries, e.g. dict.compressDict(19) instead of
  new ZstdCompressDict(dict, 19). They signal that the result is AutoCloseable
  and are for sharing one digest across contexts via refDictionary; a single
  context should prefer the context-owned loadDictionary.

Changed

• Every dictionary-id accessor now returns ZstdDictionaryId instead of int:
  ZstdDictionary.id(), ZstdCompressDict.id(), ZstdDecompressDict.id(),
  ZstdFrame.dictId(...), and ZstdFrameHeader.dictId(). The 0 sentinel is now
  ZstdDictionaryId.NONE, and the id reads as unsigned via value().
• Zstd.decompress(byte[]) now throws ZstdException (instead of letting a raw
  ArithmeticException escape) when a frame declares a content size larger than a
  Java array can hold. The size comes from the untrusted frame header; use
  decompress(byte[], int) to bound output for untrusted input.