Enhance predefined prompts with expanded selection and preview functionality

[NicolasLMP]

Why:

As a user, I need an improved interface for predefined prompts with more prompt options and the ability to select and preview prompts before submitting them, making it easier to discover and use effective queries for the chatbot.

DoD:

• Expand predefined prompts library with more diverse examples
• Add prompt selection interface with preview functionality
• Implement prompt preview display before submission
• Add prompt categorization (team_info, project_info, technical_info, feature_info)
• Create searchable prompt selection component
• Add one-click prompt submission from selection interface
• Test prompt selection UX across different screen sizes
• Validate all predefined prompts work correctly with current system

How:

• Create expanded prompt library with categorized examples
• Build Streamlit component for prompt selection with preview pane
• Add prompt search and filtering functionality by category/intent
• Implement preview display showing full prompt text before submission
• Add click-to-submit functionality from prompt selection interface
• Organize prompts by intent classification (team_info, project_info, etc.)
• Test prompt selection component integration with main chat interface
• Validate prompt effectiveness with current semantic RAG pipeline