feat: comments marked as decisions, on top of the ticket and searchable

Whoever can change the ticket flags a comment as a decision (new event
CommentDecisionMarkedEvent on the comment). The ticket page lists its
decisions above the description, with a link to the comment in the
conversation (`?comment=<id>` scrolls to it and points at it), and the
search palette finds them by their text across my projects.

API: markDecision / PUT-DELETE /api/comments/{id}/decision; Issue.decisions
and GET /api/issues/{issue}/decisions; decisions(projectId?, search) and
GET /api/projects/{project}/decisions, GET /api/me/decisions. MCP:
mark_decision, search_decisions, and get_issue includes them.

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

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

@@ -51,6 +51,9 @@ const commentFromDoc = (doc: CommentDoc): CommentReadModel => ({
   replyTo: doc.replyTo ?? null,
   deleted: doc.deleted ?? false,
   reactions: doc.reactions ?? [],
+  decision: doc.decision ?? false,
+  decidedBy: doc.decidedBy ?? null,
+  decidedAt: doc.decidedAt ?? null,
 });
 
 const escapeRegex = (text: string) =>
@@ -545,6 +548,28 @@ export class MongoFindCommentsRepository extends FindCommentsRepository {
   countReplies(commentId: string): Promise<number> {
     return this.comments.countDocuments({ replyTo: commentId });
   }
+
+  async findDecisions(filter: {
+    issueId?: string;
+    projectIds?: string[];
+    search?: string;
+    limit: number;
+  }): Promise<CommentReadModel[]> {
+    const query: Record<string, unknown> = {
+      decision: true,
+      deleted: { $ne: true },
+    };
+    if (filter.issueId) query['issueId'] = filter.issueId;
+    if (filter.projectIds) query['projectId'] = { $in: filter.projectIds };
+    if (filter.search)
+      query['body'] = { $regex: escapeRegex(filter.search), $options: 'i' };
+    const docs = await this.comments
+      .find(query)
+      .sort(filter.issueId ? { createdAt: 1 } : { decidedAt: -1 })
+      .limit(filter.limit)
+      .lean<CommentDoc[]>();
+    return docs.map(commentFromDoc);
+  }
 }
 
 @Injectable()

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

@@ -239,6 +239,10 @@ class CommentDocument {
 }
 export const CommentSchema = SchemaFactory.createForClass(CommentDocument);
 CommentSchema.index({ issueId: 1, createdAt: 1 });
+CommentSchema.index(
+  { projectId: 1, decidedAt: -1 },
+  { partialFilterExpression: { decision: true } },
+);
 
 @Schema({ ...LOOSE, collection: 'releases_view' })
 class ReleaseDocument {