feat(customer): Add create and retrieve customer from store side (#6267)

**What**
- GET /store/customers/me
- POST /store/customers
- Workflow for customer account creation
- Authentication middleware on customer routes

packages/core-flows/src/auth/index.ts

@@ -0,0 +1 @@
+export * from "./steps"

packages/core-flows/src/auth/steps/index.ts

@@ -0,0 +1 @@
+export * from "./set-auth-app-metadata"

packages/core-flows/src/auth/steps/set-auth-app-metadata.ts

@@ -0,0 +1,59 @@
+import { StepResponse, createStep } from "@medusajs/workflows-sdk"
+import { IAuthModuleService } from "@medusajs/types"
+import { ModuleRegistrationName } from "@medusajs/modules-sdk"
+import { isDefined } from "@medusajs/utils"
+
+type StepInput = {
+  authUserId: string
+  key: string
+  value: string
+}
+
+export const setAuthAppMetadataStepId = "set-auth-app-metadata"
+export const setAuthAppMetadataStep = createStep(
+  setAuthAppMetadataStepId,
+  async (data: StepInput, { container }) => {
+    const service = container.resolve<IAuthModuleService>(
+      ModuleRegistrationName.AUTH
+    )
+
+    const authUser = await service.retrieveAuthUser(data.authUserId)
+
+    const appMetadata = authUser.app_metadata || {}
+    if (isDefined(appMetadata[data.key])) {
+      throw new Error(`Key ${data.key} already exists in app metadata`)
+    }
+
+    appMetadata[data.key] = data.value
+
+    await service.updateAuthUser({
+      id: authUser.id,
+      app_metadata: appMetadata,
+    })
+
+    return new StepResponse(authUser, { id: authUser.id, key: data.key })
+  },
+  async (idAndKey, { container }) => {
+    if (!idAndKey) {
+      return
+    }
+
+    const { id, key } = idAndKey
+
+    const service = container.resolve<IAuthModuleService>(
+      ModuleRegistrationName.AUTH
+    )
+
+    const authUser = await service.retrieveAuthUser(id)
+
+    const appMetadata = authUser.app_metadata || {}
+    if (isDefined(appMetadata[key])) {
+      delete appMetadata[key]
+    }
+
+    await service.updateAuthUser({
+      id: authUser.id,
+      app_metadata: appMetadata,
+    })
+  }
+)