[12.x] Add static route cache support - backport

[DGarbs51]

Summary

Backports the Route::static() CDN-cacheable route API from the Laravel 13.x PR to Laravel 12.x.

This includes:

• the fluent Route::static() method,
• Illuminate\Routing\Middleware\CacheStaticResponse,
• request-aware static-route middleware stripping,
• final response hardening after the full HTTP middleware stack,
• default cache.static configuration,
• routing, middleware, kernel, and integration tests.

Backport Notes

The Laravel 13.x implementation uses Illuminate\Foundation\Http\Middleware\PreventRequestForgery in the default static-route middleware stripping list. Laravel 12.x uses Illuminate\Foundation\Http\Middleware\ValidateCsrfToken in the default web group, so this backport swaps the default to ValidateCsrfToken.

The rest of the behavior matches the 13.x PR:

• cacheable static requests skip configured stateful middleware,
• X-Inertia requests keep normal middleware and bypass static response mutation,
• non-cacheable methods, non-cacheable statuses, and redirects are not made static,
• cookies are stripped according to the route/config options,
• Cache-Control, optional CDN-Cache-Control, and merged Vary headers are emitted,
• the final kernel pass keeps Livewire-style global no-cache middleware from overriding static route cache headers.

Related PRs

• Laravel 13.x framework PR: [13.x] Add static route cache support #60286
• Laravel 13.x docs PR: [13.x] Document static routes docs#11214
• Laravel 12.x docs backport PR: [12.x] Document static routes - backport docs#11215

Compatibility Verification

Verified with the Herd test app against the Laravel 12.x backport branch:

• PHP 8.4 + Inertia 1 + Livewire 3: passed
• PHP 8.4 + Inertia 1 + Livewire 4: passed
• PHP 8.4 + Inertia 2 + Livewire 3: passed
• PHP 8.4 + Inertia 2 + Livewire 4: passed
• PHP 8.4 + Inertia 3 + Livewire 3: passed
• PHP 8.4 + Inertia 3 + Livewire 4: passed
• PHP 8.5 + Inertia 2 + Livewire 3: passed
• PHP 8.5 + Inertia 2 + Livewire 4: passed
• PHP 8.5 + Inertia 3 + Livewire 3: passed
• PHP 8.5 + Inertia 3 + Livewire 4: passed

Inertia 1 was not installable on PHP 8.5 because inertiajs/inertia-laravel 1.x only allows PHP through 8.4.

Tests

Run with PHP 8.4 after refreshing local dependencies for the 12.x branch:

• php84 vendor/bin/phpunit tests/Routing/RouteStaticMethodTest.php tests/Http/Middleware/CacheStaticResponseTest.php tests/Integration/Routing/RouteStaticResponseTest.php tests/Foundation/Http/KernelTest.php
• php84 vendor/bin/phpunit tests/Routing/RoutingRouteTest.php tests/Http/Middleware/CacheTest.php
• vendor/bin/pint config/cache.php src/Illuminate/Foundation/Http/Kernel.php src/Illuminate/Routing/Route.php src/Illuminate/Routing/Router.php src/Illuminate/Routing/Middleware/CacheStaticResponse.php tests/Foundation/Http/KernelTest.php tests/Routing/RouteStaticMethodTest.php tests/Http/Middleware/CacheStaticResponseTest.php tests/Integration/Routing/RouteStaticResponseTest.php