docs: Add end-to-end demo with sample dataset and example queries

[NobleCoder69]

Problem Statement

Users who clone the project and complete the setup don't know how to actually run GA4GH-RegBot to see it in action. Without a concrete example showing:

• Where to put sample GA4GH policy documents
• How to run the ingestion pipeline on them
• How to run the bot and ask it example compliance questions
• What to expect as output

New developers and evaluators cannot quickly verify that the project works as intended.

Objective

Create a minimal end-to-end demo that takes 5 minutes to run and shows GA4GH-RegBot in action.

Acceptance Criteria

1. Create examples/ directory with:

   • 2-3 small sample GA4GH policy documents (or excerpts)
   • License/attribution for each sample

2. Add examples/DEMO.md with:

   • Step-by-step commands to run the demo
   • Expected output for each command
   • 2-3 example compliance questions and RegBot's responses
   • Estimated runtime (should be < 5 minutes on standard laptop)

3. Add demo script or clear shell commands:

   • python examples/run_demo.py OR documented bash commands
   • Script should:
     • Load sample documents from examples/data/
     • Run the ingestion pipeline
     • Run 2-3 predefined queries
     • Display results clearly

4. Update README with:

   Quick Demo

Want to see GA4GH-RegBot in action? Run our 5-minute demo:

# After setup (see [Installation](#installation))
python examples/run_demo.py


## Success Metrics
✅ New user can run demo in < 5 minutes after `pip install -r requirements.txt`
✅ Demo output clearly shows RegBot answering compliance questions
✅ Demo includes at least one query result with citations
✅ All commands are copy-paste ready with no manual edits needed

## Related Issues
- Relates to: #9 (document ingestion pipeline)
- Relates to: #17 (setup documentation)

## Notes
- Keep sample documents minimal (short excerpts, not full PDFs)
- This is a documentation + light scripting task
- Perfect for users to understand the full workflow

[NobleCoder69]

Hi @dedyli

I implemented this improvement and opened a PR.

PR: #21