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>

extensions/kde/README.md

@@ -0,0 +1,50 @@
+# YAPF thumbnails for KDE (Dolphin)
+
+Shows previews of `.yapf` files in **Dolphin**, the KDE file dialogs and
+anything else that uses KIO thumbnails.  KDE Frameworks 6 / Plasma 6.
+Files with mipmaps are thumbnailed from the nearest mip level, so even huge
+textures preview instantly.
+
+## Build and install
+
+You need CMake, a C/C++ compiler and the KDE development packages:
+
+| System          | Packages |
+| :-------------- | :------- |
+| Arch / Manjaro  | `sudo pacman -S cmake extra-cmake-modules kio` |
+| Debian / Ubuntu | `sudo apt install cmake extra-cmake-modules libkf6kio-dev qt6-base-dev` |
+| Fedora          | `sudo dnf install cmake extra-cmake-modules kf6-kio-devel qt6-qtbase-devel` |
+| openSUSE        | `sudo zypper install cmake kf6-extra-cmake-modules kf6-kio-devel qt6-base-devel` |
+| NixOS           | `nix-shell kde-shell.nix` (in this folder) |
+
+```sh
+cd extensions/kde
+cmake -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr
+cmake --build build
+sudo cmake --install build
+update-mime-database /usr/share/mime
+```
+
+This installs the plugin (`kf6/thumbcreator/yapfthumbnail.so`) and the
+`image/x-yapf` file type.  Then in Dolphin: **Settings → Configure Dolphin →
+Interface → Previews**, tick **YAPF Images**, and turn previews on.
+
+### Without root (per user, also NixOS)
+
+```sh
+cmake -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$HOME/.local
+cmake --build build && cmake --install build
+update-mime-database ~/.local/share/mime
+mkdir -p ~/.config/plasma-workspace/env
+echo 'export QT_PLUGIN_PATH="$HOME/.local/lib/plugins:$QT_PLUGIN_PATH"' > ~/.config/plasma-workspace/env/yapf.sh
+```
+
+Log out and back in, then enable **YAPF Images** in Dolphin's preview settings.
+(Some distributions use `lib64/plugins` or `lib/qt6/plugins`; `cmake
+--install` prints the exact folder.)
+
+## Status
+
+Built against KF6 / Qt 6 and tested by loading the plugin through KDE's
+plugin factory and creating thumbnails (RGBA, RGB, mipmapped, wide images;
+corrupt files are rejected).  Not yet tried inside a running Dolphin.