fix: gracefully skip unreadable .env in Boot::loadDotEnv

Test ResponseSendTest::testHeaderOverride fails when tests run in random
order because the spawned process (#[RunInSeparateProcess]) calls
Boot::loadDotEnv() -> DotEnv::parse(), which throws InvalidArgument-
Exception when .env exists but is unreadable. The fix catches the
exception in loadDotEnv() so .env errors are silently ignored - .env
is optional.

Author: gr8man

system/Boot.php

@@ -206,7 +206,11 @@ protected static function loadDotEnv(Paths $paths): void
     {
         require_once $paths->systemDirectory . '/Config/DotEnv.php';
         $envDirectory = $paths->envDirectory ?? $paths->appDirectory . '/../'; // @phpstan-ignore nullCoalesce.property
-        (new DotEnv($envDirectory))->load();
+
+        try {
+            (new DotEnv($envDirectory))->load();
+        } catch (\InvalidArgumentException) {
+        }
     }
 
     protected static function defineEnvironment(): void