chore: bump pixel-mcp dependency to fork build with median-cut fix

Refreshes all 5 platform binaries from Fuitad/pixel-mcp @ e8887b3,
which fixes quantize_palette's median-cut algorithm splitting each
color bucket at the raw pixel-array midpoint instead of a boundary
between distinct colors. Pixel art typically has wildly imbalanced
color frequency (a large solid fill vastly outnumbering a 1-2px
accent detail), so splitting at the pixel-count median landed the
cut inside the dominant color's own run instead of between colors:
the dominant color got needlessly re-subdivided into near-duplicate
buckets while rare accent colors were averaged into a blended,
off-palette hex value instead of being isolated into their own
bucket, even when target_colors comfortably exceeded the number of
unique colors present (which should guarantee lossless recovery)
(upstream willibrandon/pixel-mcp#23).

Bumps plugin version to 0.5.3 and documents the change in
CHANGELOG.md.

Author: Fuitad

.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "pixel-plugin",
-  "version": "0.5.2",
+  "version": "0.5.3",
   "description": "Create, animate, and export pixel art using Aseprite through natural language and commands. Supports retro palettes, animation, dithering, and game engine export.",
   "author": {
     "name": "Brandon Williams",

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.3] - 2026-07-02
+
+### Changed
+- Updated pixel-mcp dependency to a fork build (Fuitad/pixel-mcp @ e8887b3) with a fourth fix not yet released upstream: `quantize_palette`'s median-cut algorithm split each color bucket at the raw pixel-array midpoint instead of a boundary between distinct colors. Pixel art typically has wildly imbalanced color frequency (a large solid fill vastly outnumbering a 1-2px accent detail), so splitting at the pixel-count median landed the cut inside the dominant color's own run instead of between colors: the dominant color got needlessly re-subdivided into near-duplicate buckets while rare accent colors were averaged into a blended, off-palette hex value instead of being isolated into their own bucket, even when `target_colors` comfortably exceeded the number of unique colors present (which should guarantee lossless recovery) (upstream willibrandon/pixel-mcp#23).
+- Refreshed all platform binaries (macOS Intel/ARM, Linux x86_64/ARM64, Windows x86_64) from the fork build above
+
 ## [0.5.2] - 2026-07-02
 
 ### Changed