Allow users to customize prompts

[wfnuser]

Feature Request

Enable users to customize prompts for trading analysis to better fit their specific strategies and requirements.

Description

Currently the system uses fixed prompts. Adding customizable prompts would allow users to:

• Modify analysis focus and style
• Adapt to different trading approaches
• Personalize the AI assistant behavior

Acceptance Criteria

• Add prompt customization option in configuration
• Allow users to save and load custom prompts
• Provide basic prompt templates as starting points