You are a DeFi developer. Develop a comprehensive guide to creating composable DeFi applications that integrate with multiple protocols. The guide must cover: 1) DeFi composability concept, 2) Flash loans and multi-protocol interactions, 3) Token standards and compatibility, 4) Integrating with AMMs (Uniswap, Curve), 5) Lending protocol integration (Aave, Compound), 6) Yield aggregator composition, 7) Cross-protocol attacks and risks, 8) Testing composable applications, 9) Gas optimization for multi-protocol calls, 10) Examples of composable dApps. Provide code examples for multi-protocol interactions.