fix: set global \$user stub so censor_text() does not fatal in unit tests

phpBB's real censor_text() calls smiley_text() which reads global \$user
and calls optionget().  In unit test context global \$user is null, causing
a fatal error in all fill_template-based event contract tests.  Point the
global at the existing make_user_stub() mock before each fill_template call.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: avandenberghe

tests/core/recenttopics_events_test.php

@@ -318,6 +318,10 @@ private function make_rt_for_fill_template_events(\phpbb\event\dispatcher_interf
 		// global to our test dispatcher so that call does not fatal.
 		$GLOBALS['phpbb_dispatcher'] = $dispatcher;
 
+		// phpBB's real censor_text() → smiley_text() reads global $user and
+		// calls $user->optionget().  Point it at the same user mock.
+		$GLOBALS['user'] = $this->make_user_stub();
+
 		return $rt;
 	}
 
@@ -641,6 +645,7 @@ public function test_modify_topictitle_prefix_is_applied_to_template_var()
 		$this->set_private($rt, 'total_topics_limit', 100);
 
 		$GLOBALS['phpbb_dispatcher'] = $dispatcher;
+		$GLOBALS['user'] = $this->make_user_stub();
 
 		$this->call_private($rt, 'fill_template', ['recent_topics', [], 1]);
 
@@ -768,6 +773,7 @@ public function test_modify_tpl_ary_added_key_reaches_template()
 		$this->set_private($rt, 'total_topics_limit', 100);
 
 		$GLOBALS['phpbb_dispatcher'] = $dispatcher;
+		$GLOBALS['user'] = $this->make_user_stub();
 
 		$this->call_private($rt, 'fill_template', ['recent_topics', [], 1]);