feat(promotion, dashboard, core-flows, cart, types, utils, medusa): tax inclusive promotions (#12412)

* feat: tax inclusive promotions

* feat: add a totals test case

* feat: add integration test

* chore: changeset

* fix: typo

* chore: refactor

* fix: tests

* fix: rest of buyget action tests

* fix: cart spec

* chore: expand integration test with item level totals

* feat: add a few more test cases

---------

Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/modules/promotion/src/migrations/.snapshot-medusa-promotion.json

@@ -332,6 +332,16 @@
           "default": "false",
           "mappedType": "boolean"
         },
+        "is_tax_inclusive": {
+          "name": "is_tax_inclusive",
+          "type": "boolean",
+          "unsigned": false,
+          "autoincrement": false,
+          "primary": false,
+          "nullable": false,
+          "default": "false",
+          "mappedType": "boolean"
+        },
         "type": {
           "name": "type",
           "type": "text",

packages/modules/promotion/src/migrations/Migration20250508081510.ts

@@ -0,0 +1,15 @@
+import { Migration } from "@mikro-orm/migrations"
+
+export class Migration20250508081510 extends Migration {
+  override async up(): Promise<void> {
+    this.addSql(
+      `alter table if exists "promotion" add column if not exists "is_tax_inclusive" boolean not null default false;`
+    )
+  }
+
+  override async down(): Promise<void> {
+    this.addSql(
+      `alter table if exists "promotion" drop column if exists "is_tax_inclusive";`
+    )
+  }
+}

packages/modules/promotion/src/models/promotion.ts

@@ -8,6 +8,7 @@ const Promotion = model
     id: model.id({ prefix: "promo" }).primaryKey(),
     code: model.text().searchable(),
     is_automatic: model.boolean().default(false),
+    is_tax_inclusive: model.boolean().default(false),
     type: model.enum(PromotionUtils.PromotionType).index("IDX_promotion_type"),
     status: model
       .enum(PromotionUtils.PromotionStatus)

packages/modules/promotion/src/utils/compute-actions/line-items.ts

@@ -164,6 +164,7 @@ function applyPromotionToItems(
         item_id: item.id,
         amount,
         code: promotion.code!,
+        is_tax_inclusive: promotion.is_tax_inclusive,
       })
     } else if (isTargetShippingMethod) {
       computedActions.push({