Report generation: Adding user feedback support in the form of thumbs up and thumbs down button in the UI

[lotif]

Summary

Adding thumbs up/thumbs down button to the gradio demo UI to demonstrate how to log user feedback to langfuse.

Clickup Ticket(s): NA

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update
• 🔧 Refactoring (no functional changes)
• ⚡ Performance improvement
• 🧪 Test improvements
• 🔒 Security fix

Changes Made

• Using gradio state to keep langfuse's trace id at the end of the agent's execution
• Adding a new row in the UI to capture user feedback in the form of thumbs up and thumbs down buttons that get displayed at the end of the agent's execution
• Adding events to record the user feedback into langfuse

Testing

• Tests pass locally (uv run pytest tests/)
• Type checking passes (uv run mypy <src_dir>)
• Linting passes (uv run ruff check src_dir/)
• Manual testing performed (describe below)

Manual testing details:

Clicked the buttons and checked they work in langfuse

Checklist

• Code follows the project's style guidelines
• Self-review of code completed
• Documentation updated (if applicable)
• No sensitive information (API keys, credentials) exposed