feat(cache): add device-detector cache option to improve performance

[BrianHigby]

Closes #18

Summary

Adds an opt-in cache.device-detector config option (default false) that enables the matomo/device-detector engine's own internal cache via Laravel's cache store. The default is false, so there is no behavior change for existing installs.

Requires a Laravel application context. Do not enable in standalone mode — \DeviceDetector\Cache\LaravelCache uses the Cache facade and will throw without a bootstrapped app.

Checklist

• composer test passes
• composer analyse passes (PHPStan level max, zero errors)
• Test coverage remains at 100%
• New detection methods have integration tests with real user agent strings
• New boolean flags include exclusivity assertions (setting one flag doesn't trigger unrelated flags)

Test plan

• Added test_invoke_with_device_detector_cache_enabled to DeviceDetectorTest
• Uses Cache::spy() to assert that LaravelCache actually called through to Laravel's cache store

[coveralls]

coverage: 100.0%. remained the same — BrianHigby:feat/device-detector-persistent-laravel-cache into pataar:main

[pataar]

CI is failing

[BrianHigby]

I believe the issue was Cache::spy() on Laravel 11 returns null for all calls, which caused a TypeError in LaravelCache::save() since it expects a bool return. Should be fixed now.

[pataar]

Thanks, merged!