### CHANGES
- Introduce local `chat` package for message abstraction
- Replace sashabaranov/go-openai with official openai-go SDK
- Update OpenAI, Azure, and Exolab plugins for new client
- Refactor all AI providers to use internal chat types
- Decouple codebase from third-party AI provider structs
- Replace deprecated `ioutil` functions with `os` equivalents
## CHANGES
- Add Variables field to PromptRequest struct
- Pass pattern variables through chat handler
- Create API variables documentation example
- Add pattern variables UI in web interface
- Create pattern variables store in Svelte
- Include variables in chat service requests
- Add JSON textarea for variable input
## CHANGES
- Add prompt strategies like Chain of Thought (CoT)
- Implement strategy selection with `--strategy` flag
- Improve README with platform-specific installation instructions
- Fix web interface documentation link
- Refactor git operations with new githelper package
- Add `--liststrategies` command to view available strategies
- Support applying strategies to system prompts
- Fix YouTube configuration check
- Improve error handling in session management
