feat(sales): cancellation awareness in forecast summary, productSequence ordering

- Show fully/partially cancelled products in forecast summary table
- Add cancellation KPI card with full/partial breakdown
- Fully cancelled rows: strikethrough + reduced opacity + red badge
- Partially cancelled rows: amber border + badge + effective/total qty
- Add productSequence prop to ProductsTab for custom ordering
- Fall back to CW sequenceNumber when no productSequence set
- Add productSequence field to SalesOpportunity interface

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

@@ -216,12 +216,13 @@
     </div>
     <div class="detail-pane-body">
       {#if activeTab === "Overview"}
-        <OverviewTab {opportunity} {notes} {contacts} />
+        <OverviewTab {opportunity} {notes} {contacts} {products} />
       {:else if activeTab === "Products"}
         <ProductsTab
           {products}
           accessToken={data.accessToken}
           {opportunityId}
+          productSequence={opportunity?.productSequence ?? null}
         />
       {:else if activeTab === "Notes"}
         <NotesTab