refactor: use singleton pattern for LocalConfig

php/servers/servers-rooms.php

@@ -405,9 +405,11 @@
 		 * @return int
 		 */
 		function get_staff_count(): int {
-			global $LOCAL_CONFIG;
+			$room_id = $this->get_room_identifier();
+
 			return (
-				$LOCAL_CONFIG->get_room_staff_count_override($this->get_room_identifier())
+				LocalConfig::get_instance()
+					->get_room_staff_count_override($room_id)
 				?? count($this->get_staff())
 			);
 		}

php/utils/read-config.php

@@ -13,6 +13,16 @@ class LocalConfig {
 			?? array();
 	}
 
+	private static LocalConfig | null $instance = null;
+
+	/**
+	 * Get the canonical instance of LocalConfig.
+	 * @return LocalConfig
+	 */
+	public static function get_instance(): LocalConfig {
+		return LocalConfig::$instance ??= LocalConfig::read_from_files();
+	}
+
 	private const ROOM_OVERRIDES_CONFIG = "room-overrides.ini";
 
 	private readonly array $room_overrides;
@@ -32,7 +42,7 @@ class LocalConfig {
 	/**
 	 * Read local config from the filesystem.
 	 */
-	public static function read_from_files() {
+	private static function read_from_files() {
 		return new LocalConfig();
 	}
 
@@ -46,9 +56,4 @@ class LocalConfig {
 	}
 }
 
-/**
- * @var LocalConfig $LOCAL_CONFIG
- */
-$LOCAL_CONFIG = LocalConfig::read_from_files();
-
 ?>