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>

yapf.h

@@ -232,6 +232,17 @@ yapf_image_t *yapf_load_memory_mt(const void *buffer, size_t size, int threads);
  */
 int yapf_save(const char *filename, const yapf_image_t *img);
 
+/*
+ * yapf_encode — encode an image into memory.
+ * On success *out_data points to *out_size bytes of a complete .yapf file;
+ * release it with yapf_free_buffer().  Same rules and return codes as
+ * yapf_save() (no YAPF_ERR_IO).
+ */
+int yapf_encode(const yapf_image_t *img, void **out_data, size_t *out_size);
+
+/* yapf_free_buffer — release memory returned by yapf_encode().  NULL-safe. */
+void yapf_free_buffer(void *data);
+
 /*
  * yapf_free — release all memory owned by an image returned by yapf_load().
  * NULL-safe.