Add Placement To APISubscriberCreateBody

Other Features

• api: Order-scoped shipment and label endpoints
• billing: Gate Elliot turn starts on credit balance
• builder: Offer a publish retry for stores stranded on Coming Soon
• builder: Show publish status in the version history
• checkout: Promote the preferred carrier's shipping methods
• inpost: Add configurable origin lockers
• inpost: Fallback parcel size setting and suggestion in the shipment form
• inpost: Persist shipment parameters on the order
• inpost: Suggest the locker parcel size from product dimensions
• seo: Serve noindex for non-live stores instead of blocking crawl
• shipping: Clarify carrier routes in order sidebar
• shipping: Redesign the order-sidebar shipment UI
• storefront: Auto-refresh the Coming Soon page
• subscribers: Track signup placement (which form/page drove it)