Add Qwen3 from_pretrained, generation example, and DeepseekV3 model support

[danikhan632]

✅ Qwen3 Enhancements

• New from_pretrained() method in tunix.models.qwen3.params:

  • Supports loading Qwen3 models directly from the Hugging Face Hub.
  • Automatically maps Hugging Face config (AutoConfig) to Tunix's ModelConfig.
  • Loads weights using snapshot_download and create_model_from_safe_tensors.

🧪 Qwen3 Generation Example

• Adds a standalone example script demonstrating:

  • Loading Qwen/Qwen3-0.6B from Hugging Face.
  • Using AutoTokenizer with chat templating (enable_thinking=True).
  • Running inference using Sampler with KV cache and token generation.

🚀 DeepseekV3 Model Support

• Adds full model definition for DeepseekV3:
• Supports from_pretrained() loading from Hugging Face safetensors.

[wang2yn84]

Thank you for your PR. The new model you have seems not a deepseek impl. Can you double check?