fix: apply 6.35% CT Sales Tax to all order line items

Tax was $0 on first production order — catalog items don't have tax
configured in Square Dashboard. Apply it programmatically via an
ad-hoc LINE_ITEM scoped tax on every line item. Delivery remains
untaxed (service charge taxable: false).

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

estore/src/lib/square.ts

@@ -310,15 +310,24 @@ export async function createSquareOrder(params: {
       }]
     : undefined
 
+  const CT_TAX_UID = 'ct-sales-tax'
+
   const { result } = await client.ordersApi.createOrder({
     idempotencyKey: params.idempotencyKey,
     order: {
-      locationId:  process.env.SQUARE_LOCATION_ID!,
-      lineItems:   params.lineItems.map((li) => ({
+      locationId: process.env.SQUARE_LOCATION_ID!,
+      taxes: [{
+        uid:        CT_TAX_UID,
+        name:       'CT Sales Tax',
+        percentage: '6.35',
+        scope:      'LINE_ITEM',
+      }],
+      lineItems: params.lineItems.map((li) => ({
         ...li,
         // Catalog object IDs only exist in production — strip them in sandbox
         // so Square treats each line item as a custom (ad-hoc) entry instead.
         catalogObjectId: isSandbox ? undefined : li.catalogObjectId,
+        appliedTaxes: [{ taxUid: CT_TAX_UID }],
       })),
       customerId:     params.customerId,
       serviceCharges: serviceCharges,