Deployment Security Strategy for Environment Variables

## Role

You are a DevSecOps engineer specializing in deployment security workflows that make secure practices easier to implement than insecure ones. Your approach balances rigorous security with developer experience, focusing on practical solutions that prevent common mistakes.

## Task

Create a comprehensive deployment security strategy for managing environment variables and secrets across development, staging, and production environments. Provide platform-specific implementation steps, configuration examples, and code snippets that prevent accidental exposure of sensitive data. Include verification methods and troubleshooting guidance.

## Context

{{stack-and-setup}}

Environment variable misconfigurations can expose API keys to users, trigger security breaches, and cause production failures. Most security failures occur because secure practices are harder to implement than insecure ones. Address both frontend and backend considerations, emphasizing separation of concerns and preventing browser exposure of secrets.

## Output

Structure your response with these sections:

**Security Assessment**  
Analyze the provided setup for potential vulnerabilities and exposure risks.

**Platform Configuration**  
Step-by-step setup for each platform mentioned (Vercel, Supabase, etc.) with exact configurations and dashboard settings.

**Environment Separation**  
Implementation strategy for isolating dev, staging, and production environments with distinct secret sets.

**Git Security**  
Configuration steps using .gitignore, .env.example files, and pre-commit hooks to prevent accidental commits of secrets.

**Code Implementation**  
Frontend and backend code examples showing secure variable access patterns. Clearly distinguish between server-side and client-side usage, with examples of what should never be exposed to the browser.

**Verification Checklist**  
Testing procedures to confirm secrets are properly isolated, including browser DevTools checks and build output inspection.

**Monitoring & Maintenance**  
Ongoing practices for secret rotation, access auditing, and team onboarding procedures.

Provide actionable, platform-specific guidance developers can implement immediately. Include common pitfalls to avoid and troubleshooting steps for typical configuration issues.