chore: remove dynamic and dynamic_engine modules

[skyvast404]

Summary

• remove backend dynamic module () and dynamic engine ()
• remove frontend dynamic routes/components/stores/apis and CTF mode entry
• clean backend/frontend integration points and configs referencing dynamic

Verification

• cd backend && uv run ruff check app
• cd backend && uv run mypy app --ignore-missing-imports
• cd backend && TAVILY_API_KEY=dummy uv run python -c "from app.main import app; print('ok')"
• cd frontend && pnpm run type-check
• cd frontend && pnpm run build