Add special-order product flow and improve opportunity product sequencing

src/routes/sales/opportunity/[id]/+page.svelte

@@ -20,6 +20,12 @@
   $: contacts = data.contacts;
   $: products = data.products;
   $: permissions = data.permissions;
+  let localProductSequence: number[] | null =
+    data.opportunity?.productSequence ?? null;
+
+  $: if (Array.isArray(opportunity?.productSequence)) {
+    localProductSequence = opportunity.productSequence;
+  }
 
   // Mobile detection
   let isMobile = false;
@@ -66,6 +72,10 @@
     guardedSetTab("Products");
   }
 
+  function handleSequenceSaved(e: CustomEvent<number[]>) {
+    localProductSequence = e.detail;
+  }
+
   // Mobile nav state
   let mobileActiveTab: Tab | null = null;
 
@@ -263,9 +273,10 @@
           {products}
           accessToken={data.accessToken}
           {opportunityId}
-          productSequence={opportunity?.productSequence ?? null}
+          productSequence={localProductSequence}
           initialProductId={pendingProductId}
           bind:isEditing={productsEditing}
+          on:sequenceSaved={handleSequenceSaved}
         />
       {:else if activeTab === "Notes"}
         <NotesTab