YAPF v1: fast byte-aligned format, SIMD, tools and plugins

Format (version 1, replaces the earlier experimental versions):
- per-tile YCoCg-R or subtract-green colour transform, 8-bit modular
- 12 row filters per 8-row band (Left, Gradient, Up-right, Up-average,
  Up 1-8 rows), none with more than a one-add serial dependency
- residuals in groups of 8 at the group's width (w bits x 8 = w bytes),
  4-bit control codes with repeat-previous-width runs chosen by DP
- constant and stored tiles, independent 64x64 tiles, mips, GPU hints
- all sizes validated before decoding; corrupt input is rejected

Library:
- SIMD on by default: SSSE3 (runtime CPUID check; GCC, Clang, MSVC,
  MinGW) and NEON on ARM64; -DYAPF_NO_SIMD for plain C
- yapf_load_memory, yapf_load_mt, yapf_load_memory_mt
- 6-10x faster decoding than PNG (stb_image) on one core; -O2 and -O3
  builds perform the same
- fixes for macOS (sysconf) and the Windows import library exports

Tools and integrations:
- `yapf` CLI: convert PNG/JPG/TGA/BMP/PSD/GIF <-> YAPF, info, bench,
  thumbnail, mips
- JavaScript and Python bindings (byte-identical to the C encoder)
- GIMP 3 plugin: exports the flattened image, optional mipmaps
- Blender extension: import (also as plane), export, drag and drop
- VS Code preview, Figma plugin, Photoshop scripts, Linux MIME type and
  thumbnailer
- Makefile, updated build.sh / build.bat, tools/build_release.sh
- tests/test_yapf.c (784 checks) and bindings/js/test.js

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

build.sh

@@ -8,7 +8,7 @@
 #
 #  Options:
 #    --debug        Debug build: no optimisation, full symbols
-#    --simd         Enable SIMD paths (-DYAPF_USE_SIMD)
+#    --no-simd      Plain C only (SIMD is on by default, picked at run time)
 #    --static-only  Build only static libraries
 #    --shared-only  Build only shared libraries
 #    --help         Show this message
@@ -40,14 +40,15 @@ step()  { echo; echo "${BLD}──── $* ────${RST}"; }
 
 # ── Option parsing ───────────────────────────────────────────────────
 OPT_DEBUG=0
-OPT_SIMD=0
+OPT_NOSIMD=0
 OPT_STATIC_ONLY=0
 OPT_SHARED_ONLY=0
 
 for arg in "$@"; do
     case "$arg" in
         --debug)       OPT_DEBUG=1 ;;
-        --simd)        OPT_SIMD=1 ;;
+        --no-simd)     OPT_NOSIMD=1 ;;
+        --simd)        ;;   # SIMD is the default now; kept for old scripts
         --static-only) OPT_STATIC_ONLY=1 ;;
         --shared-only) OPT_SHARED_ONLY=1 ;;
         --help)
@@ -89,7 +90,7 @@ fi
 [[ -n "$STRIP" ]] && info "Strip    : $STRIP"
 
 # ── Compiler flags ───────────────────────────────────────────────────
-CFLAGS="-std=c99 -Wall -Wextra -Wpedantic -fPIC"
+CFLAGS="-std=c99 -Wall -Wextra -Wpedantic -fPIC -pthread"
 LFLAGS=""
 
 if [[ $OPT_DEBUG -eq 1 ]]; then
@@ -101,7 +102,8 @@ else
     info "Mode     : release"
 fi
 
-[[ $OPT_SIMD -eq 1 ]] && { CFLAGS="$CFLAGS -DYAPF_USE_SIMD"; info "SIMD     : enabled"; }
+if [[ $OPT_NOSIMD -eq 1 ]]; then CFLAGS="$CFLAGS -DYAPF_NO_SIMD"; info "SIMD     : disabled"
+else info "SIMD     : SSSE3 / NEON, chosen at run time"; fi
 
 # ── Detect OS ────────────────────────────────────────────────────────
 OS=$(uname -s)
@@ -176,6 +178,13 @@ if [[ "$OS" == "Darwin" ]]; then
         ok "dist/macos/libyapf.a      (universal)"
     fi
 
+    step "Building the yapf command-line tool"
+    "$CLANG" $CFLAGS --target=arm64-apple-macos11     tools/yapf_cli.c yapf.c -o /tmp/_yapf_cli_arm64 -lm
+    "$CLANG" $CFLAGS --target=x86_64-apple-macos10.15 tools/yapf_cli.c yapf.c -o /tmp/_yapf_cli_x64 -lm
+    "$LIPO" -create /tmp/_yapf_cli_arm64 /tmp/_yapf_cli_x64 -output dist/macos/yapf
+    rm -f /tmp/_yapf_cli_arm64 /tmp/_yapf_cli_x64
+    ok "dist/macos/yapf           (universal)"
+
 # ── Linux build ──────────────────────────────────────────────────────
 elif [[ "$OS" == "Linux" ]]; then
 
@@ -205,6 +214,8 @@ elif [[ "$OS" == "Linux" ]]; then
         compile_static "$NATIVE_TRIPLE" "dist/$NATIVE_DIR/libyapf.a"
         ok "dist/$NATIVE_DIR/libyapf.a"
     fi
+    "$CLANG" $CFLAGS --target="$NATIVE_TRIPLE" tools/yapf_cli.c yapf.c -o "dist/$NATIVE_DIR/yapf" -lm
+    ok "dist/$NATIVE_DIR/yapf  (command-line tool)"
 
     # ── Cross-compile to the other common arch ────────────────────────
     if [[ "$HOST_ARCH" == "x86_64" ]]; then