Feature Request: Add more built-in tools + example tutorial for using LiteLLMModel with custom providers

[xpxxx]

✨ Feature Description

I’d like to suggest adding:

1. A richer set of built-in tools, especially for common domains such as finance, health, web scraping, and file I/O.
2. An example tutorial demonstrating how to use LiteLLMModel with different OpenAI-compatible providers (e.g., DeepSeek, Claude, Ollama) to build a custom agent.

💡 Use Case

• Tools: Having a larger pool of plug-and-play tools will make it much faster for users to prototype useful agents without building everything from scratch.
• LiteLLMModel example: Many users want to use local or cloud-hosted LLMs (e.g., DeepSeek via Ollama, Claude via Anthropic, etc.) but may not know how to properly configure LiteLLMModel with provider, base_url, and api_env_key.

Providing an end-to-end tutorial with both custom tools and model configuration would lower the entry barrier and attract more contributors and users to ISEK.

✅ Why It Benefits ISEK

• Encourages rapid prototyping and adoption.
• Helps users understand the ISEK model abstraction and tool execution pipeline.
• Promotes extensibility by showing how to integrate with other models beyond OpenAI.

🛠 Suggested Implementation

• Add a new example file (e.g., examples/deepseek_tool_agent.py) demonstrating how to:
• Configure LiteLLMModel for DeepSeek/Ollama/GPT-4/Claude
• Register basic tools (e.g., stock lookup, company info, math calculator)
• Define an IsekAgent and run .print_response() calls
• Optionally, update the documentation to include:
  • A “Getting Started with LiteLLMModel” section
  • A table of supported providers
  • Recommended base_url settings for local use (e.g., http://localhost:11434 for Ollama)