feat: customer lookup from POS with order history and item search

- Customer dialog in cart panel: search accounts by name, phone, email, account #
- Selected customer shown with name, phone, email in cart header
- accountId passed when creating transactions
- Order history view: tap a transaction to expand and see line items
- Item search in history (e.g. "strings") — filters orders containing that item
- Backend: add accountId and itemSearch filters to transaction list endpoint
- itemSearch uses EXISTS subquery on line item descriptions (ILIKE)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/backend/src/routes/v1/transactions.ts

@@ -27,6 +27,8 @@ export const transactionRoutes: FastifyPluginAsync = async (app) => {
       status: query.status,
       transactionType: query.transactionType,
       locationId: query.locationId,
+      accountId: query.accountId,
+      itemSearch: query.itemSearch,
     }
 
     const result = await TransactionService.list(app.db, params, filters)

packages/backend/src/services/transaction.service.ts

@@ -390,12 +390,20 @@ export const TransactionService = {
     status?: string
     transactionType?: string
     locationId?: string
+    accountId?: string
+    itemSearch?: string
   }) {
     const conditions: ReturnType<typeof eq>[] = []
 
     if (params.q) {
       conditions.push(buildSearchCondition(params.q, [transactions.transactionNumber])!)
     }
+    if (filters?.itemSearch) {
+      const term = `%${filters.itemSearch}%`
+      conditions.push(
+        sql`EXISTS (SELECT 1 FROM ${transactionLineItems} WHERE ${transactionLineItems.transactionId} = ${transactions.id} AND ${transactionLineItems.description} ILIKE ${term})`
+      )
+    }
     if (filters?.status) {
       conditions.push(eq(transactions.status, filters.status as any))
     }
@@ -405,6 +413,9 @@ export const TransactionService = {
     if (filters?.locationId) {
       conditions.push(eq(transactions.locationId, filters.locationId))
     }
+    if (filters?.accountId) {
+      conditions.push(eq(transactions.accountId, filters.accountId))
+    }
 
     const where = conditions.length === 0 ? undefined : conditions.length === 1 ? conditions[0] : and(...conditions)