Fix: add missing 'seed' attribute to llama_context_params initialization

[sergey21000]

Fixes #1769

Add missing seed attribute initialization to context_params in Llama class. This resolves the AttributeError that occurs when trying to deepcopy the Llama model or use it with Gradio's State component.

Previously context_params.seed was not initialized, causing:
AttributeError: 'llama_context_params' object has no attribute 'seed'

[abetlen]

@sergey21000 thank you for raising this issue, I've fixed the issue in main, the seed parameter was removed from llama.cpp so the actual value is stored in Llama._seed atm. Thank you for tracking this down!