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/README.md

@@ -0,0 +1,19 @@
+# YAPF for C# / .NET
+
+`Yapf.cs` is a single-file P/Invoke wrapper for .NET 6 or later (tested with
+.NET 8).  It should also work in Unity with the native library in
+`Assets/Plugins`, but that is not tested yet.  Add it to your project and put
+the native library next to your program: `yapf.dll` (Windows),
+`libyapf.so` (Linux) or `libyapf.dylib` (macOS) — from the
+[Releases](https://github.com/Nexoniarz/YAPF/releases) or `make`.
+
+```csharp
+using Yapf;
+
+var img = YapfImage.Load("texture.yapf");          // or YapfImage.Decode(bytes)
+byte[] pixels = img.Pixels;                         // Width * Height * Channels
+new YapfImage(256, 256, 4, rgba).Save("out.yapf");  // or .Encode() → byte[]
+```
+
+Example: `cd Example && dotnet run -- ../../../other/YAPF.YAPF`
+(Linux: `LD_LIBRARY_PATH=../../../build dotnet run …` after `make`).