class-autoloader.php listed services/ as a scan directory but not
services/opik/, where all four Opik classes live. Composer's classmap
covers includes/ recursively so PHPUnit passed; the WP runtime autoloader
fatals on first Opik class reference in production.
Root cause: the subdirectory was not added to the explicit $directories
array when the opik/ subdirectory was created in Wave 1.
Adds services/opik/ to the scan list. Bumps to v0.12.3.
5c048dd531