Add auto-detect support for --hf-chat-template

- Added 'auto' as a valid value for --hf-chat-template
- When --hf-chat-template auto is used, it auto-detects and applies HF template to all models
- Updated README with new syntax

README.md

@@ -261,6 +261,9 @@ The `--hf-chat-template` option enables using HuggingFace's `apply_chat_template
 **Usage:**
 
 ```bash
+# Auto-detect and use HuggingFace chat template for all models
+coderai --hf-chat-template auto --model llama-3.1-8b-instruct-q4_k_m.gguf
+
 # Use HuggingFace chat template for ALL text models
 coderai --hf-chat-template text --model llama-3.1-8b-instruct-q4_k_m.gguf
 
@@ -271,20 +274,21 @@ coderai --hf-chat-template text:llama-3.1 --model llama-3.1-8b-instruct-q4_k_m.g
 coderai --hf-chat-template text:llama-3.1 --hf-chat-template text:phi-3 --model llama-3.1-8b-instruct-q4_k_m.gguf
 
 # Or with Vulkan backend
-coderai --backend vulkan --hf-chat-template text --model llama-3.1-8b-instruct-q4_k_m.gguf
+coderai --backend vulkan --hf-chat-template auto --model llama-3.1-8b-instruct-q4_k_m.gguf
 ```
 
 **Syntax:**
 
 | Syntax | Applies To |
 |--------|------------|
+| `--hf-chat-template auto` | Auto-detect and use HF template for all models |
 | `--hf-chat-template text` | All text models |
 | `--hf-chat-template image` | All image models |
 | `--hf-chat-template text:model_name` | Specific text model |
 | `--hf-chat-template image:model_name` | Specific image model |
 
 **How it works:**
-1. When `--hf-chat-template` is specified for a model, the server attempts to load a HuggingFace tokenizer
+1. When `--hf-chat-template` is specified (with `auto` or a model spec), the server attempts to load a HuggingFace tokenizer
 2. It first checks for a local `tokenizer_config.json` in the model directory
 3. If not found locally, it tries to infer the model name from the GGUF filename and load from HuggingFace Hub
 4. The tokenizer's `apply_chat_template` method is then used for formatting chat messages

coderai

@@ -3132,6 +3132,9 @@ def check_hf_chat_template(model_type: str = "text", model_name: str = None) ->
         True if HF chat template should be used, False otherwise.
     
     Syntax:
+        # Auto-detect and apply to all text models
+        --hf-chat-template auto
+        
         # Apply to all text models
         --hf-chat-template text
         
@@ -3149,6 +3152,11 @@ def check_hf_chat_template(model_type: str = "text", model_name: str = None) ->
         return False
     
     for spec in hf_chat_template:
+        # Handle auto-detect - try to load HF tokenizer and auto-detect template
+        if spec == 'auto' or spec == '':
+            # Applies to all models when using 'auto'
+            return True
+        
         if ':' in spec:
             # Format: text:model_name or image:model_name
             parts = spec.split(':')
@@ -5427,7 +5435,7 @@ def parse_args():
         "--hf-chat-template",
         action="append",
         default=[],
-        help="Use HuggingFace transformers apply_chat_template for specific model(s). Format: --hf-chat-template text:model_name or --hf-chat-template text (all text models)",
+        help="Use HuggingFace transformers apply_chat_template. Use without value for auto-detect, or specify model: --hf-chat-template text:model_name. Use --hf-chat-template auto for global auto-detect.",
     )
     parser.add_argument(
         "--system-prompt",