docs: update endpoints to use file-routing approach (#5397)

- Move the original guides for creating endpoints and middlewares to sub-sections in the Endpoints category.
- Replace existing guides for endpoints and middlewares with the new approach.
- Update all endpoints-related snippets across docs to use this new approach.

www/apps/docs/content/development/fundamentals/architecture-overview.md

@@ -8,20 +8,20 @@ In this document, you'll get an overview of Medusa's architecture to better unde
 
 ## Architecture Overview
 
-Medusa's core package `@medusajs/medusa` is a Node.js backend built on top of [Express](https://expressjs.com/). It combines all the [Commerce Modules](../../modules/overview.mdx) that Medusa provides. Commerce Modules are ecommerce features that can be used as building blocks in an ecommerce ecosystem. Product is an example of a Commerce Module.
+Medusa's core package `@medusajs/medusa` is a Node.js headless server. It combines all the [Commerce Modules](../../modules/overview.mdx) that Medusa provides. Commerce Modules are ecommerce features that can be used as building blocks in an ecommerce ecosystem. Product is an example of a Commerce Module.
 
-![Medusa Core Architecture](https://res.cloudinary.com/dza7lstvk/image/upload/v1677607702/Medusa%20Docs/Diagrams/medusa-architecture-3_e385zk.jpg)
+![Medusa Core Architecture](https://res.cloudinary.com/dza7lstvk/image/upload/v1697706240/Medusa%20Docs/Diagrams/medusa_architecture_qvg9a3.jpg)
 
 The backend connects to a database, such as [PostgreSQL](https://www.postgresql.org/), to store the ecommerce store’s data. The tables in that database are represented by [Entities](../entities/overview.mdx), built on top of [Typeorm](https://typeorm.io/). Entities can also be reflected in the database using [Migrations](../entities/migrations/overview.mdx).
 
 The retrieval, manipulation, and other utility methods related to that entity are created inside a [Service](../services/overview.mdx). Services are TypeScript or JavaScript classes that, along with other resources, can be accessed throughout the Medusa backend through [dependency injection](./dependency-injection.md).
 
-The backend does not have any tightly-coupled frontend. Instead, it exposes [Endpoints](../endpoints/overview.mdx) which are REST APIs that frontends such as an admin or a storefront can use to communicate with the backend. Endpoints are [Express routes](https://expressjs.com/en/guide/routing.html).
+The backend doesn't have any tightly-coupled frontend. Instead, it exposes [API Routes](../api-routes/overview.mdx) which are REST APIs that frontends such as an admin or a storefront can use to communicate with the backend.
 
 Medusa also uses an [Events Architecture](../events/index.mdx) to trigger and handle events. Events are triggered when a specific action occurs, such as when an order is placed. To manage this events system, Medusa connects to a service that implements a pub/sub model, such as [Redis](https://redis.io/).
 
 Events can be handled using [Subscribers](../events/subscribers.mdx). Subscribers are TypeScript or JavaScript classes that add their methods as handlers for specific events. These handler methods are only executed when an event is triggered.
 
-You can create any of the resources in the backend’s architecture, such as entities, endpoints, services, and more, as part of your custom development without directly modifying the backend itself. The Medusa backend uses [loaders](../loaders/overview.mdx) to load the backend’s resources, as well as your custom resources and resources in [Plugins](../plugins/overview.mdx).
+You can create any of the resources in the backend’s architecture, such as entities, API Routes, services, and more, as part of your custom development without directly modifying the backend itself. The Medusa backend uses [loaders](../loaders/overview.mdx) to load the backend’s resources, as well as your custom resources and resources in [Plugins](../plugins/overview.mdx).
 
 You can package your customizations into Plugins to reuse them in different Medusa backends or publish them for others to use. You can also install existing plugins into your Medusa backend.

www/apps/docs/content/development/fundamentals/dependency-injection.md

@@ -16,7 +16,7 @@ Generally, all resources are registered in a container. Then, whenever a class d
 
 ### Medusa’s Dependency Container
 
-Medusa uses a dependency container to register essential resources of the backend. You can then access these resources in classes and endpoints using the dependency container.
+Medusa uses a dependency container to register essential resources of the backend. You can then access these resources in classes and API Routes using the dependency container.
 
 For example, if you create a custom service, you can access any other service registered in Medusa in your service’s constructor. That includes Medusa’s core services, services defined in plugins, or other services that you create on your backend.
 
@@ -28,7 +28,7 @@ To manage dependency injections, Medusa uses [Awilix](https://github.com/jeffijo
 
 When you run the Medusa backend, a container of the type `MedusaContainer` is created. This type extends the [AwilixContainer](https://github.com/jeffijoe/awilix#the-awilixcontainer-object) object.
 
-The backend then registers all important resources in the container, which makes them accessible in classes and endpoints.
+The backend then registers all important resources in the container, which makes them accessible in classes and API Routes.
 
 ---
 
@@ -695,11 +695,11 @@ Its camel-case name.
 
 ## Resolve Resources
 
-This section covers how to resolve resources from the dependency container to use them in endpoints and classes in general.
+This section covers how to resolve resources from the dependency container to use them in API Routes and classes in general.
 
-### In Endpoints
+### In API Routes
 
-To resolve resources, such as services, in endpoints, use the `req.scope.resolve` method. The method receives the registration name of the resource as a parameter.
+To resolve resources, such as services, in API Routes, use the `MedusaRequest` object's `scope.resolve` method. The method receives the registration name of the resource as a parameter.
 
 For example:
 
@@ -707,7 +707,7 @@ For example:
 const logger = req.scope.resolve("logger")
 ```
 
-Please note that in endpoints some resources, such as repositories, are not available. Refer to the [repositories](../entities/repositories.md) documentation to learn how you can load them.
+Please note that in API Routes some resources, such as repositories, aren't available. Refer to the [repositories](../entities/repositories.md#api-routes) documentation to learn how you can load them.
 
 ### In Classes
 

www/apps/docs/content/development/fundamentals/local-development.md

@@ -104,7 +104,7 @@ yarn test
 
 ### Run API Integration Tests
 
-API integration tests are used to test out Medusa’s core endpoints.
+API integration tests are used to test out Medusa’s core API Routes.
 
 To run the API integration tests, run the following command in the root directory of the repository: