Better Auth Lead Plugin

The `better-auth-lead` package is a plugin for the `better-auth` ecosystem, designed to extend its core functionality with lead management capabilities. It facilitates features like newsletter sign-ups, waitlists, and general lead capture by providing a dedicated database table (`leads`) and a robust API. Currently at version 0.4.0, the package is in active development, implying potential API changes in minor versions before reaching a stable 1.0 release. Key differentiators include its seamless integration with `better-auth`'s server and client infrastructure, built-in support for email verification with customizable sending logic, and the ability to define and validate lead metadata using standard schema libraries like Zod or Valibot. This allows developers to quickly add lead generation features with strong type safety and validation.