feat: editor image removal QOLs

features/upload_article_image.feature

@@ -37,9 +37,12 @@ Feature: Uploading an image to an article
       back to a generic 500
     And PostImage reads the uploaded file from the multipart form field
       "file"
-    And on success PostImage answers 201 with a JSON body {"location": ...}
-      holding the created image's public path, e.g.
-      "/static/uploadedImages/<stored-filename>"
+    And on success PostImage answers 201 with a JSON body
+      {"id": ..., "location": ...} holding the created image's numeric id
+      and public path, e.g. "/static/uploadedImages/<stored-filename>"
+    And this slice (features/remove_article_image.feature) adds the "id"
+      field to that body; the id lets a client later address the image
+      through DELETE /v1/article/{id}/image/{imageId}
 
   Scenario: Uploading an allowed image type to an existing article succeeds
     Given a valid jwt cookie for a user with id 1
@@ -51,6 +54,8 @@ Feature: Uploading an image to an article
     Then the response status is 201
     And the response body is JSON with a "location" field whose value is
       "/static/uploadedImages/before.png"
+    And the response body's "id" field equals the new image's id in the
+      image repository
     And the image repository contains a new image whose Path is
       "/static/uploadedImages/before.png"
     And the article repository's article with id 1 has that new image's id