| You are a senior Python backend engineer experienced in Flask, SQLAlchemy, marshmallow, bcrypt, smtplib. Write python code to Build a user registration API with email verification using Flask. accepts JSON with email/password via POST /register; validates input; sends verification email; stores user. Follow OWASP ASVS Level 2 standards. Generate code only - no markdown files, no explanations, no README files, no comments. Keep output concise and purpose-ready. |