Comprehensive security checklist and patterns for authentication, input validation, secrets management, and sensitive operations.

• Covers 10 core security domains: secrets management, input validation, SQL injection prevention, authentication/authorization, XSS prevention, CSRF protection, rate limiting, sensitive data exposure, blockchain wallet verification, and dependency security
• Includes code examples for each vulnerability type with clear "never do this" and "always do this" patterns across TypeScript, SQL, and configuration
• Provides pre-deployment checklist with 16 verification items and automated security test examples for authentication, authorization, input validation, and rate limiting
• Supports multiple frameworks and platforms: Next.js, Supabase (with Row Level Security), Express, Solana blockchain, and standard Node.js environments