feat: conversations on a ticket are settled, and you see who is typing

A top-level comment and its replies can be resolved by whoever can
change the ticket (CommentThreadResolvedEvent), with an optional
conclusion added as a reply marked as a decision, so it shows above the
ticket. A settled conversation folds to one line (topic, who settled it
and the conclusion) and can be unfolded or reopened; the header counts
the open ones, and finishing the ticket with one open asks first.

«Ana está escribiendo…» shows in the conversation being answered, at
once: a `typing` mutation publishes to a Redis channel per ticket
(`typing` subscription), never stored. In replies, Enter sends and
Shift+Enter breaks the line, except inside lists and code.

API: resolveThread / PUT-DELETE /api/comments/{id}/resolution, Comment
.resolved/resolvedBy/resolvedAt, typing mutation and subscription. MCP:
resolve_thread.

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

apps/api/schema.gql

@@ -310,6 +310,13 @@ type Comment {
 
   """The top-level comment it answers; null for a top-level one"""
   replyTo: ID
+
+  """A conversation (top-level comment and its replies) that was settled"""
+  resolved: Boolean!
+  resolvedAt: String
+
+  """Who settled it"""
+  resolvedBy: UserRef
   version: Int!
 }
 
@@ -1049,6 +1056,11 @@ type Mutation {
   removeGitRepository(projectId: ID!, repositoryId: ID!): Boolean!
   removeProjectMember(projectId: ID!, userId: ID!): CommandResult!
 
+  """
+  Settle a conversation (a top-level comment and its replies) or reopen it (resolved: false). A conclusion is added as a reply marked as a decision. Whoever can change the ticket
+  """
+  resolveThread(commentId: ID!, conclusion: String, resolved: Boolean! = true): CommandResult!
+
   """Back from the trash"""
   restoreIssue(issueId: ID!): CommandResult!
 
@@ -1105,6 +1117,16 @@ type Mutation {
   """
   trashIssue(issueId: ID!): CommandResult!
 
+  """
+  I am writing on this ticket (send every few seconds while typing): those with it open see it at once via `typing`
+  """
+  typing(
+    issueId: ID!
+
+    """The conversation being answered; null: a new comment"""
+    threadId: ID
+  ): Boolean!
+
   """Bring an archived project back (owner only)"""
   unarchiveProject(projectId: ID!): CommandResult!
   unlinkIssues(input: LinkIssuesInput!): CommandResult!
@@ -1988,6 +2010,11 @@ type Subscription {
   projectChanged(projectId: ID!): ProjectChange!
   releaseChanged(projectId: ID!): ReleaseChange!
   sprintChanged(projectId: ID!): SprintChange!
+
+  """
+  Who is writing on a ticket, as they type (one's own come too: leave them out)
+  """
+  typing(issueId: ID!): Typing!
 }
 
 type Suggestion {
@@ -2038,6 +2065,16 @@ type Throughput {
   week: String!
 }
 
+"""Someone writing on a ticket right now (not stored)"""
+type Typing {
+  at: String!
+  issueId: ID!
+
+  """The conversation being answered; null: a new comment"""
+  threadId: ID
+  user: UserRef!
+}
+
 input UpdateChecklistItemInput {
   done: Boolean
   issueId: ID!