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/csharp/Example/Example.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="../Yapf.cs" />
+  </ItemGroup>
+</Project>

bindings/csharp/Example/Program.cs

@@ -0,0 +1,25 @@
+// dotnet run -- ../../../other/YAPF.YAPF   (with yapf.dll / libyapf.so on the library path)
+using System.Diagnostics;
+using Yapf;
+
+string path = args.Length > 0 ? args[0] : "../../../other/YAPF.YAPF";
+byte[] file = File.ReadAllBytes(path);
+
+var img = YapfImage.Decode(file);                 // first call also loads the library / JIT
+double ms = double.MaxValue;                      // best of 10, as in a running program
+for (int i = 0; i < 10; i++)
+{
+    var sw = Stopwatch.StartNew();
+    img = YapfImage.Decode(file);
+    ms = Math.Min(ms, sw.Elapsed.TotalMilliseconds);
+}
+Console.WriteLine($"{path}: {img.Width}x{img.Height}, {img.Channels} channels, decoded in {ms:F2} ms");
+Console.WriteLine($"file is {file.Length} bytes, {100.0 * file.Length / img.Pixels.Length:F1}% of the raw pixels");
+
+byte[] again = img.Encode();
+Console.WriteLine($"re-encoded: {again.Length} bytes, identical: {again.AsSpan().SequenceEqual(file)}");
+
+var rgba = new byte[64 * 64 * 4];
+for (int i = 0; i < rgba.Length; i += 4) { rgba[i] = (byte)(i / 4 % 64 * 4); rgba[i + 1] = 100; rgba[i + 2] = 200; rgba[i + 3] = 255; }
+new YapfImage(64, 64, 4, rgba).Save("csharp.yapf");
+Console.WriteLine("wrote csharp.yapf");