✨ Add Toast notification component

[damienlagae]

Summary

Adds a new Enabel:Ux:Toast Twig component wrapping Bootstrap 5's toast pattern, designed for non-intrusive notifications (flash messages, status updates, async operation results).

Why

The existing Enabel:Ux:Alert component renders an inline alert in the document flow, which is fine for inline forms feedback but not ideal for transient notifications: it pushes content around, doesn't auto-dismiss, doesn't stack natively, and isn't tuned for screen reader politeness levels.

The Toast component renders Bootstrap's native toast markup with the right ARIA attributes and configurable behaviors, so consumers can drop it into a .toast-container and forget about the boilerplate.

API

{{ component('Enabel:Ux:Toast', {
    text: 'Saved successfully',
    type: 'success',
    autohide: true,
    delay: 5000,
    dismissible: true,
    politeness: 'polite',
}) }}

Parameter	Type	Default
text	?string	null
type	string	'info'
dismissible	bool	true
autohide	bool	true
delay	int	5000
politeness	string	'polite'

Accessibility

• role=\"alert\" + aria-live=\"{politeness}\" + aria-atomic=\"true\" on the toast root
• politeness: 'polite' for non-urgent messages (default), assertive for errors / urgent feedback
• btn-close-white applied automatically except on warning and light backgrounds (dark text on light fill)

Initialization

Like the native Bootstrap toast, the component renders the markup but does not display it. Bootstrap's JS must be invoked to show it. The doc includes a one-method Stimulus controller covering all toasts inside a container:

import { Controller } from '@hotwired/stimulus';
import { Toast } from 'bootstrap';

export default class extends Controller {
    connect() {
        this.element.querySelectorAll('.toast').forEach(el => {
            Toast.getOrCreateInstance(el).show();
        });
    }
}

Test plan

• PHPUnit (full suite green: 195 tests, 547 assertions — 10 new tests for Toast)
• PHPStan level 8 — no errors
• PHP-CS-Fixer (`@Symfony` + `:risky`) — no violations
• Visual smoke test in a consumer project (success/danger/warning/info, auto-hide, dismiss button color, multiple toasts stacking, content block override)

Notes

• New component, no breaking change.
• Documentation added at `docs/Toast/toast.md` and linked from `docs/index.md`.
• A follow-up could ship a Stimulus controller in the bundle (similar to Modal's `assets/dist/modal.js`) so consumers don't have to write the show/init themselves. Kept out of this PR to keep it focused on the Twig component.