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>

libs/api/tracker/infrastructure/src/lib/mongo/find.repositories.ts

@@ -58,6 +58,7 @@ const commentFromDoc = (doc: CommentDoc): CommentReadModel => ({
   resolved: doc.resolved ?? false,
   resolvedBy: doc.resolvedBy ?? null,
   resolvedAt: doc.resolvedAt ?? null,
+  spawned: doc.spawned ?? [],
 });
 
 const escapeRegex = (text: string) =>

libs/api/tracker/infrastructure/src/lib/mongo/issue-visits.repository.ts

@@ -0,0 +1,30 @@
+import { Injectable } from '@nestjs/common';
+import { InjectModel } from '@nestjs/mongoose';
+import {
+  IssueVisit,
+  IssueVisitsRepository,
+} from '@task-stream/api/tracker/application';
+import { Model } from 'mongoose';
+import { ReadModels } from './read-model.schemas';
+
+@Injectable()
+export class MongoIssueVisitsRepository extends IssueVisitsRepository {
+  constructor(
+    @InjectModel(ReadModels.IssueVisit)
+    private readonly visits: Model<IssueVisit>,
+  ) {
+    super();
+  }
+
+  async visit(visit: IssueVisit): Promise<string | null> {
+    // One round trip: the document as it was before this visit.
+    const before = await this.visits
+      .findOneAndUpdate(
+        { userId: visit.userId, issueId: visit.issueId },
+        { $set: { seenAt: visit.seenAt } },
+        { upsert: true, new: false },
+      )
+      .lean<IssueVisit>();
+    return before?.seenAt ?? null;
+  }
+}

libs/api/tracker/infrastructure/src/lib/mongo/read-model.schemas.ts

@@ -110,6 +110,7 @@ export const ReadModels = {
   AlertIntegration: 'AlertIntegration',
   AlertTrace: 'AlertTrace',
   TreeFollow: 'TreeFollow',
+  IssueVisit: 'IssueVisit',
   IssueReminder: 'IssueReminder',
   MyDay: 'MyDay',
   ReleaseNotesShare: 'ReleaseNotesShare',
@@ -373,6 +374,16 @@ export const TreeFollowSchema =
   SchemaFactory.createForClass(TreeFollowDocument);
 TreeFollowSchema.index({ userId: 1, issueId: 1 }, { unique: true });
 
+@Schema({ ...LOOSE, collection: 'issue_visits' })
+class IssueVisitDocument {
+  @Prop({ type: String }) userId!: string;
+  @Prop({ type: String }) issueId!: string;
+  @Prop({ type: String }) seenAt!: string;
+}
+export const IssueVisitSchema =
+  SchemaFactory.createForClass(IssueVisitDocument);
+IssueVisitSchema.index({ userId: 1, issueId: 1 }, { unique: true });
+
 @Schema({ ...LOOSE, collection: 'issue_reminders' })
 class IssueReminderDocument {
   @Prop({ type: String, required: true, unique: true }) id!: string;
@@ -511,6 +522,7 @@ export const READ_MODEL_SCHEMAS = [
   { name: ReadModels.AlertIntegration, schema: AlertIntegrationSchema },
   { name: ReadModels.AlertTrace, schema: AlertTraceSchema },
   { name: ReadModels.TreeFollow, schema: TreeFollowSchema },
+  { name: ReadModels.IssueVisit, schema: IssueVisitSchema },
   { name: ReadModels.IssueReminder, schema: IssueReminderSchema },
   { name: ReadModels.MyDay, schema: MyDaySchema },
   { name: ReadModels.ReleaseNotesShare, schema: ReleaseNotesShareSchema },

libs/api/tracker/infrastructure/src/lib/tracker-infrastructure.module.ts

@@ -16,6 +16,7 @@ import {
   PinsRepository,
   AlertIntegrationsRepository,
   TreeFollowsRepository,
+  IssueVisitsRepository,
   IssueRemindersRepository,
   MyDaysRepository,
   ReleaseNoteSharesRepository,
@@ -87,6 +88,7 @@ import { MongoMyViewsRepository } from './mongo/my-views.repository';
 import { MongoPinsRepository } from './mongo/pins.repository';
 import { MongoAlertIntegrationsRepository } from './mongo/alert-integrations.repository';
 import { MongoTreeFollowsRepository } from './mongo/tree-follows.repository';
+import { MongoIssueVisitsRepository } from './mongo/issue-visits.repository';
 import { MongoIssueRemindersRepository } from './mongo/issue-reminders.repository';
 import { MongoMyDaysRepository } from './mongo/my-days.repository';
 import { MongoReleaseNoteSharesRepository } from './mongo/release-note-shares.repository';
@@ -172,6 +174,7 @@ const PORTS = [
     useClass: MongoAlertIntegrationsRepository,
   },
   { provide: TreeFollowsRepository, useClass: MongoTreeFollowsRepository },
+  { provide: IssueVisitsRepository, useClass: MongoIssueVisitsRepository },
   {
     provide: IssueRemindersRepository,
     useClass: MongoIssueRemindersRepository,