feat(container): add Magento app adapter

[wpoortman]

Summary

• route app() through a Magento-backed application container
• preserve shared Magento get() behavior for ordinary resolution
• forward explicit constructor parameters through Magento create()
• support Magento preferences, virtual types, and Magewire aliases
• provide the retained Livewire has(), singleton(), and instance() compatibility surface
• keep application bindings exclusively in Magento di.xml; intentionally omit runtime bind()
• preserve legacy ObjectManager-compatible get(), create(), and configure() methods

Verification

• 14 PHPUnit tests, 45 assertions
• focused Mago formatting and lint checks pass
• Magento frontend bootstrap verifies shared identity, contextual parameters, preferences, virtual types, and aliases
• Portman build succeeds and leaves dist/ unchanged

Follow-up coverage

Illuminate 13, adminhtml, and the broader supported Magento/Mage-OS matrix remain recorded as follow-up checks in the feature plan.

Plan

.agents/plans/feat-2026-08-13-app-helper-parity/PLAN.md