feat: teams within a project

Projects keep teams of members in their settings (settings.teams; people
outside the project are dropped, teams are archived, not removed; absent
when saving means unchanged). Tickets go to a team (`team`, also filtered
in the list and in MCP search_issues), and a comment mentioning
@[Frontend](team-FRONT) tells each of its members. Settings has the teams
with their members, the ticket a «Equipo» select, the list a team filter,
and «@» offers the teams after the people.

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

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

@@ -428,6 +428,7 @@ export function issueFromDoc(doc: IssueDoc): IssueReadModel {
     parent: rest.parent?.id ? rest.parent : null,
     rank: rest.rank ?? implicitRank(rest.number),
     startDate: rest.startDate ?? null,
+    team: rest.team ?? null,
     customFields: rest.customFields ?? {},
     sprint: rest.sprint?.id ? rest.sprint : null,
     // Links recorded before projects had several repositories name none.