feat: what is new since my last visit, and turning a comment into a ticket

Opening a ticket notes the visit and answers the one before (issue_visits),
so the page marks others' comments and changes since. A comment can become
a ticket of its own, as a subtask or linked; it remembers where it went.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/schema.gql

@@ -318,6 +318,9 @@ type Comment {
 
   """Who settled it"""
   resolvedBy: UserRef
+
+  """Tickets made from it («Convertir en ticket»), oldest first"""
+  spawned: [CommentSpawn!]!
   version: Int!
 }
 
@@ -354,6 +357,12 @@ type CommentReaction {
   users: [UserRef!]!
 }
 
+"""A ticket made from a comment"""
+type CommentSpawn {
+  id: ID!
+  key: String!
+}
+
 type CountByAssignee {
   count: Int!
 
@@ -1209,6 +1218,18 @@ type Mutation {
   """
   trashIssue(issueId: ID!): CommandResult!
 
+  """
+  Make a ticket of a comment: its text becomes the description, as a subtask of its ticket or linked to it (RELATES_TO). Answers the new ticket. Whoever can change tickets
+  """
+  turnCommentIntoIssue(
+    asSubtask: Boolean! = false
+    commentId: ID!
+    title: String!
+
+    """One of the project's ticket type ids"""
+    type: String!
+  ): CommandResult!
+
   """
   I am writing on this ticket (send every few seconds while typing): those with it open see it at once via `typing`
   """
@@ -1258,6 +1279,11 @@ type Mutation {
   updateSprint(input: UpdateSprintInput!): CommandResult!
   updateWebhook(input: UpdateWebhookInput!): Webhook!
 
+  """
+  I opened this ticket now: answers when I had opened it before (null: never), to show what is new since
+  """
+  visitIssue(issueId: ID!): String
+
   """
   Vote for a ticket (on) or take the vote back: anyone signed in on a public project, members on a private one
   """