feat: complete inventory image and sales workflows

Commit the working vertical slices for inventory image processing and the Sale workflow, including Sale history, audited voiding, multi-item persistence, admin UI, migrations, documentation, and tests.

apps/api/src/infrastructure/database/schema.js

@@ -297,4 +297,46 @@ export const listings = pgTable('listings', {
 }, (table) => [
   index('listings_inventory_item_id_index').on(table.inventoryItemId),
   index('listings_status_index').on(table.status),
-]);
+]);
+
+export const sales = pgTable('sales', {
+  id: uuid('id').defaultRandom().primaryKey(),
+  sellerId: uuid('seller_id')
+    .notNull()
+    .references(() => sellers.id),
+  status: text('status').default('COMPLETED').notNull(),
+  saleDate: text('sale_date').notNull(),
+  saleLocation: text('sale_location'),
+  soldPriceMinor: integer('sold_price_minor').notNull(),
+  currency: text('currency').notNull(),
+  platformFeesMinor: integer('platform_fees_minor').default(0).notNull(),
+  paymentProcessingFeesMinor: integer('payment_processing_fees_minor').default(0).notNull(),
+  shippingCostMinor: integer('shipping_cost_minor').default(0).notNull(),
+  taxesMinor: integer('taxes_minor').default(0).notNull(),
+  otherFeesMinor: integer('other_fees_minor').default(0).notNull(),
+  buyerName: text('buyer_name'),
+  buyerContact: text('buyer_contact'),
+  notes: text('notes'),
+  voidReason: text('void_reason'),
+  voidedAt: timestamp('voided_at', { withTimezone: true }),
+  ...timestamps,
+});
+
+export const saleItems = pgTable(
+  'sale_items',
+  {
+    id: uuid('id').defaultRandom().primaryKey(),
+    saleId: uuid('sale_id')
+      .notNull()
+      .references(() => sales.id),
+    inventoryItemId: uuid('inventory_item_id')
+      .notNull()
+      .references(() => inventoryItems.id),
+    soldPriceMinor: integer('sold_price_minor').notNull(),
+    costBasisMinor: integer('cost_basis_minor').notNull(),
+  },
+  (table) => [
+    uniqueIndex('sale_items_inventory_item_id_unique').on(table.inventoryItemId),
+    index('sale_items_sale_id_index').on(table.saleId),
+  ],
+);