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>

Makefile

@@ -0,0 +1,65 @@
+# YAPF — simple build for Linux, macOS and other Unix systems.
+#
+#   make                 library (static + shared) and the `yapf` tool, in build/
+#   make test            run the C test suite (and the JS one if node is present)
+#   sudo make install    install header, libraries and tool under $(PREFIX)
+#   make NO_SIMD=1       plain C only
+#
+# Windows: use build.bat (LLVM) or any MinGW / MSVC compiler on yapf.c.
+
+CC      ?= cc
+CFLAGS  ?= -O2
+PREFIX  ?= /usr/local
+BUILD   ?= build
+
+YAPF_CFLAGS = -std=c99 -Wall -Wextra $(CFLAGS) $(if $(NO_SIMD),-DYAPF_NO_SIMD)
+LDLIBS      = -lm -pthread
+
+ifeq ($(shell uname -s),Darwin)
+  SHARED = libyapf.dylib
+  SHARED_FLAGS = -dynamiclib -install_name $(PREFIX)/lib/libyapf.dylib
+else
+  SHARED = libyapf.so
+  SHARED_FLAGS = -shared
+endif
+
+all: $(BUILD)/libyapf.a $(BUILD)/$(SHARED) $(BUILD)/yapf
+
+$(BUILD):
+	mkdir -p $(BUILD)
+
+$(BUILD)/yapf.o: yapf.c yapf.h | $(BUILD)
+	$(CC) $(YAPF_CFLAGS) -fPIC -c yapf.c -o $@
+
+$(BUILD)/libyapf.a: $(BUILD)/yapf.o
+	$(AR) rcs $@ $^
+
+$(BUILD)/$(SHARED): $(BUILD)/yapf.o
+	$(CC) $(SHARED_FLAGS) $^ -o $@ -pthread
+
+$(BUILD)/yapf: tools/yapf_cli.c yapf.c yapf.h | $(BUILD)
+	$(CC) $(YAPF_CFLAGS) tools/yapf_cli.c yapf.c -o $@ $(LDLIBS)
+
+$(BUILD)/test_yapf: tests/test_yapf.c yapf.c yapf.h | $(BUILD)
+	$(CC) $(YAPF_CFLAGS) tests/test_yapf.c yapf.c -o $@ $(LDLIBS)
+
+test: $(BUILD)/test_yapf
+	$(BUILD)/test_yapf other/YAPF.YAPF
+	@if command -v node >/dev/null 2>&1; then node bindings/js/test.js; \
+	 else echo "(node not found: skipped the JavaScript tests)"; fi
+
+install: all
+	install -d $(DESTDIR)$(PREFIX)/include $(DESTDIR)$(PREFIX)/lib $(DESTDIR)$(PREFIX)/bin
+	install -m 644 yapf.h $(DESTDIR)$(PREFIX)/include/yapf.h
+	install -m 644 $(BUILD)/libyapf.a $(DESTDIR)$(PREFIX)/lib/libyapf.a
+	install -m 755 $(BUILD)/$(SHARED) $(DESTDIR)$(PREFIX)/lib/$(SHARED)
+	install -m 755 $(BUILD)/yapf $(DESTDIR)$(PREFIX)/bin/yapf
+
+uninstall:
+	rm -f $(DESTDIR)$(PREFIX)/include/yapf.h $(DESTDIR)$(PREFIX)/lib/libyapf.a \
+	      $(DESTDIR)$(PREFIX)/lib/$(SHARED) $(DESTDIR)$(PREFIX)/bin/yapf
+
+clean:
+	rm -rf $(BUILD)
+
+.PHONY: all test install uninstall clean