feat(orders): credit each order to the expert who placed it, as legacy did

Legacy fixed `orders.reagent_id` once, when the order was placed, and its
«میزان فروش» summed `customer_id = X OR reagent_id = X`. The app credited
orders to the customer's CURRENT referrer and left out an expert's own
orders, so 9 of 49 imported experts showed a different figure.

- Order.salesAgentId (+ referrerCustomerId for 17 legacy orders whose
  referrer was not an expert); additive migration, recent app orders
  backfilled from the customer's referrer
- createOrder records the expert at placement time
- one shared filter (agent-orders.ts) for the experts list, expert
  detail, dashboard and the expert app; child orders follow salesAgentId
- customer page gets its «میزان فروش» back
- import carries orders.reagent_id as is; ex-experts kept as admins keep
  their profile so their own orders stay linked
- reconcile-sales: 1,557 of 1,558 match legacy's own formula; balances
  unchanged

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/scripts/legacy-import/index.ts

@@ -32,7 +32,7 @@ import { IdMap, makeContext, openSource, type Ctx, type Options } from './lib/co
 import { admins, branches, cities, customers, experts, roles, workshops } from './steps/people';
 import { brands, categories, products, variants } from './steps/catalog';
 import { favorites, ledger, orders, preOrders } from './steps/commerce';
-import { reconcile } from './steps/reconcile';
+import { reconcile, reconcileSales } from './steps/reconcile';
 
 /** Order matters: each step reads the ids the earlier ones mapped. */
 const STEPS: [string, (ctx: Ctx) => Promise<void>][] = [
@@ -52,6 +52,7 @@ const STEPS: [string, (ctx: Ctx) => Promise<void>][] = [
   ['favorites', favorites],
   ['preorders', preOrders],
   ['reconcile', reconcile],
+  ['reconcile-sales', reconcileSales],
 ];
 
 const ENTITIES = [