feat: a dashboard for clients, behind a secret link

Owners and admins turn it on in Configuración → General, pick what it
shows (tickets per status, the sprint under way, release forecasts,
open epics and activity per day) and can renew or drop the link. Whoever
has it sees /share/{token} without an account: only those blocks, no
people nor single tickets but the epics, no links into the app, read
again every minute. A renewed or dropped link says it no longer works.

REST (GET/PUT/DELETE /api/projects/{project}/share and the public
GET /api/shared/dashboards/{token}) and GraphQL (dashboardShare,
shareDashboard, unshareDashboard, sharedDashboard). The token is kept
in dashboard_shares and goes with the project.

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

libs/api/tracker/domain/src/lib/read-models/shared-dashboard.read-model.ts

@@ -0,0 +1,59 @@
+import {
+  ActivityDayReadModel,
+  ReleaseForecastReadModel,
+  SprintPulseReadModel,
+} from './insights.read-model';
+
+/** The blocks a project can show to outsiders, in the order they are shown. */
+export const SHARED_BLOCKS = [
+  'flow',
+  'sprint',
+  'releases',
+  'epics',
+  'activity',
+] as const;
+export type SharedBlock = (typeof SHARED_BLOCKS)[number];
+
+/** A project's link for clients: the secret, and what it shows. */
+export class DashboardShareReadModel {
+  projectId!: string;
+  /** Random and long; whoever has it sees the chosen blocks. */
+  token!: string;
+  blocks!: SharedBlock[];
+  createdAt!: string;
+}
+
+/** Tickets in one status (the board's columns, archived ones left out). */
+export class SharedFlowReadModel {
+  status!: string;
+  name!: string;
+  /** A colour name of the project's settings. */
+  color!: string;
+  count!: number;
+}
+
+/** An open epic and how far it got: no more than its key and title. */
+export class SharedEpicReadModel {
+  key!: string;
+  title!: string;
+  dueDate!: string | null;
+  done!: number;
+  total!: number;
+  percent!: number;
+}
+
+/**
+ * What a client sees through the link: only the chosen blocks (the others
+ * are null), nothing about people or single tickets but the epics.
+ */
+export class SharedDashboardReadModel {
+  projectKey!: string;
+  projectName!: string;
+  generatedAt!: string;
+  blocks!: SharedBlock[];
+  flow!: SharedFlowReadModel[] | null;
+  sprint!: SprintPulseReadModel | null;
+  releases!: ReleaseForecastReadModel[] | null;
+  epics!: SharedEpicReadModel[] | null;
+  activity!: ActivityDayReadModel[] | null;
+}