feat: add Printify order submission and fulfilment tracking

Submit paid orders to Printify via provider API with idempotent
guards, Stripe address mapping, and error handling. Track fulfilment
status through submitted → processing → shipped → delivered via
webhook-driven updates (primary) and Oban Cron polling fallback.

- 9 fulfilment fields on orders (status, provider IDs, tracking, timestamps)
- OrderSubmissionWorker with retry logic, auto-enqueued after Stripe payment
- FulfilmentStatusWorker polls every 30 mins for missed webhook events
- Printify order webhook handlers (sent-to-production, shipment, delivered)
- Admin UI: fulfilment column in table, fulfilment card with tracking info,
  submit/retry and refresh buttons on order detail
- Mox provider mocking for test isolation (Provider.for_type configurable)
- 33 new tests (555 total), verified against real Printify API

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

test/simpleshop_theme_web/live/admin_live/orders_test.exs

@@ -115,5 +115,76 @@ defmodule SimpleshopThemeWeb.AdminLive.OrdersTest do
       {:error, {:live_redirect, %{to: "/admin/orders"}}} =
         live(conn, ~p"/admin/orders/#{fake_id}")
     end
+
+    test "shows fulfilment card", %{conn: conn} do
+      order = order_fixture(payment_status: "paid")
+
+      {:ok, _view, html} = live(conn, ~p"/admin/orders/#{order}")
+
+      assert html =~ "Fulfilment"
+      assert html =~ "unfulfilled"
+    end
+
+    test "shows submit button for paid unfulfilled orders", %{conn: conn} do
+      order = order_fixture(payment_status: "paid")
+
+      {:ok, _view, html} = live(conn, ~p"/admin/orders/#{order}")
+
+      assert html =~ "Submit to provider"
+    end
+
+    test "shows retry button for failed fulfilment", %{conn: conn} do
+      order = order_fixture(payment_status: "paid")
+
+      {:ok, order} =
+        SimpleshopTheme.Orders.update_fulfilment(order, %{fulfilment_status: "failed"})
+
+      {:ok, _view, html} = live(conn, ~p"/admin/orders/#{order}")
+
+      assert html =~ "Retry submission"
+    end
+
+    test "shows refresh button for submitted orders", %{conn: conn} do
+      {order, _v, _p, _c} =
+        SimpleshopTheme.OrdersFixtures.submitted_order_fixture()
+
+      {:ok, _view, html} = live(conn, ~p"/admin/orders/#{order}")
+
+      assert html =~ "Refresh status"
+    end
+
+    test "shows tracking info when available", %{conn: conn} do
+      {order, _v, _p, _c} =
+        SimpleshopTheme.OrdersFixtures.submitted_order_fixture()
+
+      {:ok, order} =
+        SimpleshopTheme.Orders.update_fulfilment(order, %{
+          fulfilment_status: "shipped",
+          tracking_number: "TRACK123",
+          tracking_url: "https://track.example.com/TRACK123",
+          shipped_at: DateTime.utc_now() |> DateTime.truncate(:second)
+        })
+
+      {:ok, _view, html} = live(conn, ~p"/admin/orders/#{order}")
+
+      assert html =~ "TRACK123"
+      assert html =~ "https://track.example.com/TRACK123"
+    end
+  end
+
+  describe "order list fulfilment column" do
+    setup %{conn: conn, user: user} do
+      conn = log_in_user(conn, user)
+      %{conn: conn}
+    end
+
+    test "shows fulfilment badge in table", %{conn: conn} do
+      order_fixture(payment_status: "paid")
+
+      {:ok, _view, html} = live(conn, ~p"/admin/orders")
+
+      assert html =~ "Fulfilment"
+      assert html =~ "unfulfilled"
+    end
   end
 end