Add LLaDA 8b Diffusion model (#14771)

* Add support for Llada-8b: diffusion model

* Add README

* Fix README and convert_hf_to_gguf

* convert_hf_to_gguf.py: address review comments

* Make everything in a single example

* Remove model-specific sampling

* Remove unused argmax

* Remove braced initializers, improve README.md a bit

* Add diffusion specific gguf params in set_vocab, remove setting rope_theta and rms_norm_eps

* Remove adding the mask token

* Move add_add_bos_token to set_vocab

* use add_bool in gguf_writer.py

gguf-py/gguf/gguf_writer.py

@@ -1047,6 +1047,11 @@ class GGUFWriter:
     def add_audio_stack_factor(self, value: int) -> None:
         self.add_uint32(Keys.ClipAudio.Projector.STACK_FACTOR, value)
 
+    # diffusion models
+
+    def add_diffusion_shift_logits(self, value: bool) -> None:
+        self.add_bool(Keys.Diffusion.SHIFT_LOGITS, value)
+
     def _pack(self, fmt: str, value: Any, skip_pack_prefix: bool = False) -> bytes:
         pack_prefix = ''
         if not skip_pack_prefix: