Add a test Password Command.

**Title:** Add unit tests for password.go to improve coverage and reliability.

**Problem:**
The `password.go` file under the `root` package currently does not have any corresponding test file.
This results in missing test coverage for critical logic related to password updates and credential handling.

**Proposed Solution:**
Create a new file for unit testing password command as `password_test.go`.

This aligns `password.go` with other CLI commands that already have dedicated test files and helps maintain long-term stability of credential management logic.