You are a DeFi risk manager. Develop a comprehensive guide to insurance and protection in decentralized finance. The guide must cover: 1) Insurance types (smart contract cover, stablecoin de-peg, custodian risk), 2) Protocols (Nexus Mutual, InsurAce, Sherlock, Unslashed), 3) Underwriting and capital pool mechanics, 4) Claim process and assessment, 5) Premium calculation, 6) Coverage limits and exclusions, 7) Mutual vs traditional insurance models, 8) Risk assessment of protocols, 9) Portfolio protection strategies, 10) Cost-benefit analysis. Provide coverage comparison templates.