Add MakeAdminCommand and improve taskfile consistency

[roble]

This pull request introduces a new Artisan command to promote users to admin, along with supporting tests and improvements to developer tooling. It also updates the auth database seeder and makes minor adjustments to E2E test configuration.

New Admin Promotion Command:

• Added the auth:make-admin Artisan command (MakeAdminCommand) to promote an existing user to admin, with argument validation and clear output.
• Registered the new command in the Taskfile.yml under the make-admin task for easy execution.

Testing:

• Added feature tests (MakeAdminCommandTest) to ensure the new command works correctly, including scenarios for successful promotion, user-not-found, role replacement, and idempotency.

Database Seeding:

• Updated AuthDatabaseSeeder to only create a default user with the user role, removing automatic assignment of the admin role and test user creation.

Developer Tooling:

• Updated task commands in Taskfile.yml to consistently use the {{.APP}} variable for environment compatibility.

E2E Test Configuration:

• Set the top-level "Login Security" test suite to run in serial mode, and removed redundant serial configuration from the nested "Rate Limiting" suite for clarity. [1] [2]