feat: editor write path

features/article_title_rules.feature

@@ -1,4 +1,5 @@
 Feature: The article title rule is the same in the request and the domain
+  Superseded in part by article_edit_revision: titles are editable.
   Superseded in part by roles_permissions_content_scope: the article routes are gated by the content.* permissions of the caller's role (content.create, content.update, content.delete and content.publish; a refusal is 403 "missing_permission" with the header X-Missing-Permission), and content.read decides which drafts show: every draft at all, only the caller's own drafts at own, none otherwise. A draft the caller may not read answers 404 "Article not found", and a role that cannot be resolved is treated as holding no permission.
 
   As the maintainer of RenewCMS
@@ -26,9 +27,7 @@ Feature: The article title rule is the same in the request and the domain
       500 with body "Failed to create article"
     And POST /v1/article/ sits behind the jwtauth Verifier and Authenticator group and
       requires a valid jwt cookie
-    And UpdateArticleUseCase exposes only UpdateBody, AddImage and UpdateIsOnline; no
-      route or use case updates an article's title after creation, so this feature only
-      concerns article creation
+    And PATCH /v1/article/{id} accepts `title` with the same 3-200 rune rule, rejected as 400 with apperr.ArticleTitleErrorMessage (see features/article_edit_revision.feature)
 
   Scenario Outline: CreateArticle now measures title length in runes, not bytes
     Given an empty article repository fake
@@ -76,6 +75,34 @@ Feature: The article title rule is the same in the request and the domain
     And the response body is the text apperr.ArticleTitleErrorMessage
     And the response body is not "Failed to create article"
 
+  Scenario Outline: PATCH /v1/article/{id} enforces the same 3-200 rune boundary
+    Given a valid jwt cookie for a user holding content.update
+    And the article repository contains an article with id 1
+    When the client sends PATCH /v1/article/1 with that cookie and a title of <length> ASCII characters
+    Then the response status is <status>
+    And <storage_effect>
+
+    Examples:
+      | length | status | storage_effect        |
+      | 2      | 400    | the title is unchanged |
+      | 3      | 200    | the title is stored    |
+      | 200    | 200    | the title is stored    |
+      | 201    | 400    | the title is unchanged |
+
+  Scenario: A domain title rejection on update is a 400, not a 500
+    Given a valid jwt cookie for a user holding content.update
+    And the article repository fake is configured so its next Update call returns article.ErrInvalidTitle
+    When the client sends PATCH /v1/article/1 with that cookie and title "Valid Title"
+    Then the response status is 400
+    And the response body is the text apperr.ArticleTitleErrorMessage
+
+  Scenario: Editing the title does not change the slug
+    Given a valid jwt cookie for a user holding content.update
+    And the article with id 1 has slug "backyard-renovation-update"
+    When the client sends PATCH /v1/article/1 with that cookie and title "A brand new title"
+    Then the response status is 200
+    And the slug is still "backyard-renovation-update"
+
   Scenario: A non-title repository failure during creation still answers 500
     Given a valid jwt cookie for a user with id 1
     And the article repository fake is configured to fail on its next Create call with