feat(utils): define file config (#13283)

** What
 - Allow auto-loaded Medusa files to export a config object.
 - Currently supports isDisabled to control loading.
 - new instance `FeatureFlag` exported by `@medusajs/framework/utils`
 - `feature-flags` is now a supported folder for medusa projects, modules, providers and plugins. They will be loaded and added to `FeatureFlag`

** Why
 - Enables conditional loading of routes, migrations, jobs, subscribers, workflows, and other files based on feature flags.

```ts
// /src/feature-flags

import { FlagSettings } from "@medusajs/framework/feature-flags"

const CustomFeatureFlag: FlagSettings = {
  key: "custom_feature",
  default_val: false,
  env_key: "FF_MY_CUSTOM_FEATURE",
  description: "Enable xyz",
}

export default CustomFeatureFlag
```

```ts
// /src/modules/my-custom-module/migration/Migration20250822135845.ts

import { FeatureFlag } from "@medusajs/framework/utils"

export class Migration20250822135845 extends Migration {
  override async up(){ }
  override async down(){ }
}

defineFileConfig({
  isDisabled: () => !FeatureFlag.isFeatureEnabled("custom_feature")
})
```

integration-tests/modules/__tests__/order/draft-order.spec.ts

@@ -1,7 +1,5 @@
 import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import {
-  ICartModuleService,
-  IFulfillmentModuleService,
   IInventoryServiceNext,
   IPricingModuleService,
   IProductModuleService,
@@ -24,7 +22,7 @@ import { setupTaxStructure } from "../fixtures"
 
 jest.setTimeout(100000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 
 medusaIntegrationTestRunner({
   env,

integration-tests/modules/__tests__/order/order.spec.ts

@@ -16,7 +16,7 @@ import {
 
 jest.setTimeout(50000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 
 medusaIntegrationTestRunner({
   env,

integration-tests/modules/__tests__/order/workflows/begin-order-claim.spec.ts

@@ -23,7 +23,7 @@ import {
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 const providerId = "manual_test-provider"
 
 async function prepareDataFixtures({ container }) {

integration-tests/modules/__tests__/order/workflows/begin-order-exchange.spec.ts

@@ -25,7 +25,7 @@ import {
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 const providerId = "manual_test-provider"
 
 async function prepareDataFixtures({ container }) {

integration-tests/modules/__tests__/order/workflows/begin-order-return.spec.ts

@@ -21,7 +21,7 @@ import {
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 const providerId = "manual_test-provider"
 
 async function prepareDataFixtures({ container }) {

integration-tests/modules/__tests__/order/workflows/cancel-order.spec.ts

@@ -3,6 +3,7 @@ import {
   cancelOrderWorkflow,
   createOrderFulfillmentWorkflow,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import {
   IOrderModuleService,
   InventoryItemDTO,
@@ -17,12 +18,11 @@ import {
   Modules,
   remoteQueryObjectFromString,
 } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "./__fixtures__"
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 
 medusaIntegrationTestRunner({
   env,

integration-tests/modules/__tests__/order/workflows/claim/claim-shipping.spec.ts

@@ -6,18 +6,18 @@ import {
   orderClaimRequestItemReturnWorkflow,
   updateClaimAddItemWorkflow,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { IFulfillmentModuleService, OrderDTO } from "@medusajs/types"
 import {
   ContainerRegistrationKeys,
   Modules,
   remoteQueryObjectFromString,
 } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "../__fixtures__"
 jest.setTimeout(50000)
 
 medusaIntegrationTestRunner({
-  env: { MEDUSA_FF_MEDUSA_V2: true },
+  env: {},
   testSuite: ({ getContainer }) => {
     let container
 

integration-tests/modules/__tests__/order/workflows/create-complete-return.spec.ts

@@ -25,7 +25,7 @@ import {
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 const providerId = "manual_test-provider"
 
 async function prepareDataFixtures({ container }) {

integration-tests/modules/__tests__/order/workflows/create-fulfillment.spec.ts

@@ -24,7 +24,7 @@ import {
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 const providerId = "manual_test-provider"
 const variantSkuWithInventory = "test-variant"
 let inventoryItem

integration-tests/modules/__tests__/order/workflows/create-shipment.spec.ts

@@ -24,7 +24,7 @@ import {
 
 jest.setTimeout(500000)
 
-const env = { MEDUSA_FF_MEDUSA_V2: true }
+const env = {}
 const providerId = "manual_test-provider"
 let inventoryItem
 

integration-tests/modules/__tests__/order/workflows/exchange/exchange-shipping.spec.ts

@@ -6,18 +6,18 @@ import {
   orderExchangeRequestItemReturnWorkflow,
   updateExchangeAddItemWorkflow,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { IFulfillmentModuleService, OrderDTO } from "@medusajs/types"
 import {
   ContainerRegistrationKeys,
   Modules,
   remoteQueryObjectFromString,
 } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "../__fixtures__"
 jest.setTimeout(50000)
 
 medusaIntegrationTestRunner({
-  env: { MEDUSA_FF_MEDUSA_V2: true },
+  env: {},
   testSuite: ({ getContainer }) => {
     let container
 

integration-tests/modules/__tests__/order/workflows/order-change-actions.ts

@@ -7,6 +7,7 @@ import {
   updateOrderChangeActionsWorkflow,
   updateOrderChangeActionsWorkflowId,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import {
   IOrderModuleService,
   OrderChangeActionDTO,
@@ -14,13 +15,12 @@ import {
   OrderDTO,
 } from "@medusajs/types"
 import { ChangeActionType, Modules } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "./__fixtures__"
 
 jest.setTimeout(50000)
 
 medusaIntegrationTestRunner({
-  env: { MEDUSA_FF_MEDUSA_V2: true },
+  env: {},
   testSuite: ({ getContainer }) => {
     let container
 

integration-tests/modules/__tests__/order/workflows/order-change.spec.ts

@@ -7,15 +7,15 @@ import {
   deleteOrderChangeWorkflow,
   deleteOrderChangeWorkflowId,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { IOrderModuleService, OrderChangeDTO, OrderDTO } from "@medusajs/types"
 import { Modules } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "./__fixtures__"
 
 jest.setTimeout(50000)
 
 medusaIntegrationTestRunner({
-  env: { MEDUSA_FF_MEDUSA_V2: true },
+  env: {},
   testSuite: ({ getContainer }) => {
     let container
 

integration-tests/modules/__tests__/order/workflows/return/create-return-shipping.spec.ts

@@ -5,18 +5,18 @@ import {
   requestItemReturnWorkflow,
   updateRequestItemReturnWorkflow,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { IFulfillmentModuleService, OrderDTO, ReturnDTO } from "@medusajs/types"
 import {
   ContainerRegistrationKeys,
   Modules,
   remoteQueryObjectFromString,
 } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "../__fixtures__"
 jest.setTimeout(50000)
 
 medusaIntegrationTestRunner({
-  env: { MEDUSA_FF_MEDUSA_V2: true },
+  env: {},
   testSuite: ({ getContainer }) => {
     let container
 

integration-tests/modules/__tests__/order/workflows/return/items.spec.ts

@@ -3,19 +3,19 @@ import {
   createOrderFulfillmentWorkflow,
   requestItemReturnWorkflow,
 } from "@medusajs/core-flows"
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { IOrderModuleService, OrderDTO, ReturnDTO } from "@medusajs/types"
 import {
   ContainerRegistrationKeys,
   Modules,
   remoteQueryObjectFromString,
 } from "@medusajs/utils"
-import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
 import { createOrderFixture, prepareDataFixtures } from "../__fixtures__"
 
 jest.setTimeout(50000)
 
 medusaIntegrationTestRunner({
-  env: { MEDUSA_FF_MEDUSA_V2: true },
+  env: {},
   testSuite: ({ getContainer }) => {
     let container