Language bindings, KDE thumbnails, yapf compare, in-memory encoding

- yapf_encode() / yapf_free_buffer(): encode to memory; yapf_save uses it
- yapf.c also compiles as C++
- `yapf compare`: size and decode speed of the original format vs YAPF,
  with a lossless check
- bindings with tested examples: C++ (header-only), C# (P/Invoke),
  Rust (crate, builds the C code), Go (cgo), Java (FFM API, Java 22+),
  Zig (@cImport), LuaJIT (FFI), TypeScript types for the JS port;
  Python now encodes in memory
- docs/LANGUAGES.md and examples/ with measured results
- KDE Dolphin thumbnail plugin (KF6, CMake)
- README: honest status for Photoshop / VS Code / Figma (not run in the
  apps yet) and macOS (cross-compiled only), platform table

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

bindings/go/yapf_test.go

@@ -0,0 +1,46 @@
+package yapf
+
+import (
+	"bytes"
+	"os"
+	"testing"
+)
+
+func TestRoundtrip(t *testing.T) {
+	for ch := 1; ch <= 4; ch++ {
+		w, h := 97, 61
+		px := make([]byte, w*h*ch)
+		for i := range px {
+			px[i] = byte(i*7 ^ i>>5)
+		}
+		data, err := Encode(&Image{Width: w, Height: h, Channels: ch, Flags: FlagSRGB, Pixels: px})
+		if err != nil {
+			t.Fatal(err)
+		}
+		back, err := Decode(data)
+		if err != nil || !bytes.Equal(back.Pixels, px) {
+			t.Fatalf("roundtrip failed for %d channels", ch)
+		}
+	}
+}
+
+func TestSampleReencodesIdentically(t *testing.T) {
+	file, err := os.ReadFile("../../other/YAPF.YAPF")
+	if err != nil {
+		t.Skip("sample not found")
+	}
+	img, err := Decode(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	again, _ := Encode(img)
+	if !bytes.Equal(again, file) {
+		t.Fatal("re-encoded sample differs from the C encoder's output")
+	}
+}
+
+func TestRejectsGarbage(t *testing.T) {
+	if _, err := Decode([]byte("not an image")); err == nil {
+		t.Fatal("garbage was accepted")
+	}
+}