v0.5.2

Added

• PNG IHDR read parity: Filter and Interlace with reference PrintConv
  strings, SRGBRendering from the sRGB chunk.
• PNG zTXt chunk support (zlib/deflate; Node parser layer).
• PNG tEXt/iTXt/zTXt keywords surface as bare capitalized tag names
  (parameters → Parameters), yielding to EXIF/eXIf/XMP-derived keys.
• XMP read parity: unknown-namespace properties surface with capitalized
  local names (InvokeAI Metadata/Graph, DMI DigitalSourceType,
  GPano panorama tags with integer typing); xmpMM:History flattens to
  History* fields and the raw container is no longer emitted; XMP dates
  with Z suffix normalize to EXIF-style rendering; TAG_REMAP entries
  pinned for exif:UserComment, InvokeAI, DMI, GPano/IGPano.
• src/ai-parity.test.ts: reference-equal tests against real exiftool on
  A1111 (tEXt parameters) and InvokeAI (XMP/DMI/History) fixtures.

Fixed

• pngWriter omitted the IEND CRC — every PNG written by the library was
  truncated by 4 bytes and unreadable by strict parsers.