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/batch-jobs/create.mdx

@@ -288,7 +288,7 @@ If you follow along with the JS Client code snippets, make sure to [install and
 
 ### Create Batch Job
 
-The first step is to create a batch job using the [Create Batch Job endpoint](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobs). In the body of the request, you must set the `type` to the value of `batchType` in the batch job strategy you created.
+The first step is to create a batch job using the [Create Batch Job API Route](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobs). In the body of the request, you must set the `type` to the value of `batchType` in the batch job strategy you created.
 
 For example, this creates a batch job of the type `publish-products`:
 

www/apps/docs/content/development/batch-jobs/customize-import.md

@@ -103,7 +103,7 @@ npm run build
 
 Since you didn’t create a new batch job type and overwrote the functionality of the strategy, you can test out your functionality using the [same steps used with the default strategy](./create.mdx#test-your-batch-job-strategy).
 
-Specifically, since you create batch jobs using the [Create Batch Job](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobs) endpoint which accepts the batch job type as a body parameter, you just need to send the same type you used for this field. In the example of this documentation, the `type` would be `product-import`.
+Specifically, since you create batch jobs using the [Create Batch Job API Route](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobs) which accepts the batch job type as a body parameter, you just need to send the same type you used for this field. In the example of this documentation, the `type` would be `product-import`.
 
 If you overwrote the import functionality, you can follow [these steps to learn how to import products using the Admin APIs](../../modules/products/admin/import-products.mdx).
 

www/apps/docs/content/development/batch-jobs/index.mdx

@@ -49,15 +49,15 @@ When you create a batch job strategy, the `batchType` class property indicates t
 
 A batch job’s flow from creation to completion is:
 
-1. A batch job is created using the [Create Batch Job API endpoint](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobs).
+1. A batch job is created using the [Create Batch Job API route](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobs).
 2. Once the batch job is created, the batch job’s status is changed to `created` and the `batch.created` event is triggered by the `BatchJobService`.
 3. The `BatchJobSubscriber` handles the `created` event. It resolves the batch job strategy based on the `type` of the batch job, then uses it to pre-process the batch job. After this, the batch job’s status is changed to `pre_processed`. Only when the batch job has the status `pre_processed` can be confirmed.
-4. If `dry_run` is not set in the Create Batch Job request in step one or if it is set to `false`, the batch job will automatically be confirmed after processing. Otherwise, if `dry_run` is set to `true`, the batch job can be confirmed using the [Confirm Batch Job API](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobsbatchjobconfirmprocessing) endpoint.
+4. If `dry_run` is not set in the Create Batch Job request in step one or if it is set to `false`, the batch job will automatically be confirmed after processing. Otherwise, if `dry_run` is set to `true`, the batch job can be confirmed using the [Confirm Batch Job API Route](https://docs.medusajs.com/api/admin#batch-jobs_postbatchjobsbatchjobconfirmprocessing).
 5. Once the batch job is confirmed, the batch job’s status is changed to `confirmed` and the `batch.confirmed` event is triggered by the `BatchJobService`.
 6. The `BatchJobSubscriber` handles the `confirmed` event. It resolves the batch job strategy, then uses it to process the batch job. 
 7. Once the batch job is processed successfully, the batch job has the status `completed`.
 
-You can track the progress of the batch job at any point using the [Retrieve Batch Job](https://docs.medusajs.com/api/admin#batch-jobs_getbatchjobsbatchjob) endpoint.
+You can track the progress of the batch job at any point using the [Retrieve Batch Job API Route](https://docs.medusajs.com/api/admin#batch-jobs_getbatchjobsbatchjob).
 
 :::info