[codex] Hide clear cache button on simple pages

[howdu]

Summary

• skip rendering the clear-cache Livewire button when the current Filament route is unauthenticated or a SimplePage
• add hiddenOnSimplePages(false) as an opt-out for panels that still want the button on simple pages
• cover unauthenticated, simple-page, opt-out, and normal dashboard rendering behavior

Root cause

The package registers its button globally on panels::user-menu.before. Filament simple/auth pages can render the simple user menu area, so the hook could place the trash icon in the top-right of auth and required MFA setup flows.

Validation

• vendor/bin/pint --dirty --format agent
• composer test -- --filter=FilamentClearCachePluginTest
• composer test