feat: a home page with life

Greeting and summary of the day, the coming week, the latest across my
projects, who is online now, the week in numbers (mine and the team's,
with a streak), sprints under way, «Retomar», project cards with their
activity, what to pick up when nothing is mine and first steps for
newcomers. REST (GET /api/me/home), GraphQL (myHome) and MCP
(get_my_week).

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

libs/web/tracker/domain/src/lib/models/models.ts

@@ -378,6 +378,8 @@ export interface Release {
 export interface Activity {
   id: string;
   type: string;
+  /** Absent in activity read before it carried the project. */
+  projectId?: string;
   issueId: string | null;
   issueKey: string | null;
   actor: UserRef;