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/web/tracker/application/src/lib/facades/facades.spec.ts

@@ -234,6 +234,7 @@ describe('ProjectFacade', () => {
       issueTypes: [],
       areas: [],
       customFields: [],
+      teams: [],
     };
 
     project.saveSettings(settings);

libs/web/tracker/application/src/lib/facades/project.facade.ts

@@ -1,6 +1,7 @@
 import { computed, inject, Injectable, Provider } from '@angular/core';
 import { injectDispatch } from '@ngrx/signals/events';
 import {
+  TEAM_MENTION_PREFIX,
   CreateReleaseInput,
   CreateSprintInput,
   ProjectRole,
@@ -25,6 +26,20 @@ export class ProjectFacade {
 
   readonly project = this.store.project;
   readonly members = this.store.members;
+  /**
+   * Who `@` offers: the members, then the active teams (a team's mention,
+   * `team-<id>`, tells each of its members).
+   */
+  readonly mentionable = computed(() => [
+    ...this.store.members().map((m) => m.user),
+    ...this.store
+      .workflow()
+      .activeTeams()
+      .map((t) => ({
+        id: `${TEAM_MENTION_PREFIX}${t.id}`,
+        name: `${t.name} · equipo`,
+      })),
+  ]);
   readonly stats = this.store.stats;
   readonly releases = this.store.releases;
   /** Under way, planned, then closed; with their progress. */