Implement dashboard parsing and delivery sensors

Reads delivery day, next arrival date, both upcoming carts, box contents,
add-ons and order totals from a single /p/dashboard/details fetch. Adds five
sensors and parser tests over a synthetic fixture mirroring the live markup.

Records two portal quirks: every /p/ path returns 200 so signed-in state is
detected by a Sign Out control, and cart-contents-skipped marks the locked
cart rather than a skipped order.

custom_components/freshharvest/strings.json

@@ -20,9 +20,10 @@
   "entity": {
     "sensor": {
       "next_delivery": { "name": "Next delivery" },
-      "order_total": { "name": "Order total" },
-      "status": { "name": "Order status" },
-      "item_count": { "name": "Items in box" }
+      "next_delivery_total": { "name": "Next delivery total" },
+      "next_delivery_items": { "name": "Next delivery items" },
+      "open_order_delivery": { "name": "Open order delivery" },
+      "shop_window": { "name": "Shopping window" }
     }
   }
 }