This commit introduces a new command, `/core:env`, to manage environment variables. It provides a set of tools to compare and manage a local `.env` file against a `.env.example` template, with a strong emphasis on security by masking sensitive values.
The command includes the following subcommands:
- `/core:env`: Shows the current environment variables with sensitive values masked.
- `/core:env check`: Validates the local `.env` file against `.env.example`, reporting any missing or required variables.
- `/core:env diff`: Displays the differences between the `.env` and `.env.example` files, ensuring sensitive data is not exposed.
- `/core:env sync`: Adds missing variables from `.env.example` to the local `.env` file without overwriting existing values.
To prevent accidental exposure of secrets, the `.env` file is now included in `.gitignore`.
