LiveView for creating and editing goods receipts.

Handles:

• :new — creates an empty draft and redirects to :edit.
• :edit — loads an existing receipt; :general tab.
• :lines — verification sheet: ordered_quantity (read-only) beside editable received_quantity.
• :files — MediaBrowser; storage folder resolved asynchronously.
• :comments — goods receipt comments thread.

Uses the admin header-breadcrumb pattern: use PhoenixKitWeb, :live_view + a self_wrapped_layout on_mount wrapping render/1 in <LayoutWrapper.app_layout> (title in the global admin header). No streams. All navigation paths wrapped in PhoenixKit.Utils.Routes.path/1.