Give browser tests on CI more time and wait for Alpine in the theme test

CI's WebKit job failed twice on a slow runner: a carousel scroll that had
not settled within five seconds, and a press on the theme switch before
Alpine had revealed it. BROWSER_TIMEOUT raises the assertion timeout, and
the workflow sets it to fifteen seconds.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

tests/Pest.php

@@ -3,3 +3,9 @@
 use NoNameWeb\LivewireMaterial\Tests\TestCase;
 
 pest()->extend(TestCase::class)->in('Feature', 'Browser');
+
+// A shared CI runner is slower than a workstation: an animation or a smooth scroll can take longer
+// than the default five seconds to settle there. BROWSER_TIMEOUT (milliseconds) raises the limit.
+if (($timeout = (int) getenv('BROWSER_TIMEOUT')) > 0) {
+    pest()->browser()->timeout($timeout);
+}