feat(auth): install Fortify and wire backend authentication flows

[ibourgeois]

Goal

Add Laravel Fortify backend authentication flows for the app's initial account model.

Scope

• Install and configure Fortify
• Enable login and logout flows
• Enable password reset flow
• Support admin-created-user onboarding only

Out of Scope

• Public self-registration
• Role management UI
• Final branded auth pages

Acceptance Criteria

• Fortify is installed and serving the required auth backend flows
• Users created by admins can authenticate and reset passwords
• Guest and authenticated route behavior is correct

Dependencies

• Depends on chore(frontend): install and configure Livewire and icon package #3

Test Plan

• Add feature tests for login, logout, forgot password, and reset password flows
• Verify guest and authenticated redirects