llama, server: add /v1/systemone API (models: laya, julia-1, lev, openjev, kev) (#29818)

* init conversion

* convert: ok

* model loaded

* add server code

* improve conversion script

* support shared prompt prefix

* add docs, imorove UX a bit

* add vision support

* add openjev tiny model for testing

* add dev docs

* support lev & kev

* clean up

* fix lev noul

* fix py lint

* nits docs

* clarify about not supporting date_facts

conversion/base.py

@@ -1268,22 +1268,24 @@ class ModelBase:
         return inner
 
     @staticmethod
-    def load_hparams(dir_model: Path, is_mistral_format: bool):
+    def load_hparams(dir_model: Path, is_mistral_format: bool, guess: bool = True):
         if is_mistral_format:
             with open(dir_model / "params.json", "r", encoding="utf-8") as f:
                 config = json.load(f)
             return config
 
+        # checkpoints with a non-HF layout are matched by their own loader
+        # models with a HF layout can also register a hparams loader to switch to a custom class
+        config = ModelBase.load_hparams_guess(dir_model) if guess and dir_model.is_dir() else None
+        if config is not None:
+            return config
+
         try:
             # for security reason, we don't allow loading remote code by default
             # if a model need remote code, we will fallback to config.json
             config = AutoConfig.from_pretrained(dir_model, trust_remote_code=False).to_dict()
         except Exception as e:
             logger.warning(f"Failed to load model config from {dir_model}: {e}")
-            if not (dir_model / "config.json").is_file():
-                config = ModelBase.load_hparams_guess(dir_model)
-                if config is not None:
-                    return config
             logger.warning("Trying to load config.json instead")
             with open(dir_model / "config.json", "r", encoding="utf-8") as f:
                 config = json.load(f)
@@ -1936,6 +1938,9 @@ class TextModel(ModelBase):
         if chkhsh == "653660222fb704f61cbf2b618a8ae6502b7f8b20c980f9a5de07ed78e13319cd":
             # ref: https://huggingface.co/ufakai/ufakzeka-1
             res = "ufakzeka"
+        if chkhsh == "4b05e02dad1c5ae07d266fd3342ddb644c6f6be058d728bc0a33af31a1d6ee66":
+            # ref: https://huggingface.co/jhu-clsp/mmBERT-base
+            res = "mmbert"
 
         if res is None:
             logger.warning("\n")
@@ -2880,6 +2885,11 @@ else:
     LazyTorchTensor._dtype_str_map["F8_E8M0"] = torch.uint8
 
 
+def jinja_str_or_json(name: str) -> str:
+    # jinja expression that renders a variable as-is if it is a string, as JSON otherwise
+    return "{{ " + name + " if " + name + " is string else " + name + " | tojson }}"
+
+
 def get_model_architecture(hparams: dict[str, Any], model_type: ModelType) -> str:
     # TODO @ngxson : this won't work correctly if the model has both audio & vision encoders
     # maybe we should fallback to text model's arch in that case, since not many models have both