docs: update docs

[emilylm]

📌 Summary

This PR updates existing documentation - both the README.md and docs in the docs/ dir. It also adds handover docs (docs/handover).

🔄 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 change)
• 🧹 Refactor (code change that neither fixes a bug nor adds a feature)
• 📚 Documentation update
• ⚙️ CI / build / tooling change

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🧩 Key Changes

• Update documentation: README.md and handover docs
• Remove outdated broker endpoints (have removed the routes but left the actual functions - tagged for clean up)

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✅ Checklist

• Tests are passing locally / in CI
• New tests have been added for new or changed functionality
• Self-review completed
• Documentation updated (if needed)
• No sensitive data or secrets included

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🔍 Review Notes

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📎 Related Issues / Tickets

• Closes #
• Related to #

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