asc v0.18.3

Added

• Product Page Optimization tests — asc experiments list|get|create|update|start|stop|delete, asc experiment-treatments list|create|update|delete, and asc experiment-treatment-localizations list|create|delete manage App Store product page A/B tests (ASC API appStoreVersionExperiments v2). A test is app-scoped; create takes --name, --platform and --traffic-proportion 1-100; start/stop map to PATCH { started: true|false }. New AppStoreVersionExperiment (+ AppStoreVersionExperimentState with isEditable/isPendingReview/isApproved/isFinished, and isRunning/canStart on the model), ExperimentTreatment and ExperimentTreatmentLocalization domain types in Domain/Apps/Experiments/, backed by ExperimentRepository. Affordances are state-aware: createTreatment/update/delete only while editable, start only when approved and unstarted, stop only while running. App gains a listExperiments affordance for discovery. REST equivalents under /api/v1/apps/:appId/experiments, /api/v1/experiments/:id[/start|/stop|/experiment-treatments], /api/v1/experiment-treatments/:id[/experiment-treatment-localizations] and /api/v1/experiment-treatment-localizations/:id via ExperimentsController. See docs/features/product-page-optimization.md.