feat: «Mi día», the few tickets I pick for today

A home panel with the tickets picked for today (10 at most), crossed out
as they get done and counted («1 de 3 terminados»), my open tickets to
add with one click, and what was left unfinished on my last day to carry
over. «☀ Mi día» on a ticket adds it or takes it out. The day is the
person's own (YYYY-MM-DD from the browser); private, no history (Mongo
`my_days`).

API: myDay(day), addToMyDay, removeFromMyDay; GET /api/me/day,
PUT/DELETE /api/me/day/{issue}. MCP: my_day.

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

libs/web/tracker/domain/src/lib/ports/gateways.ts

@@ -1,4 +1,5 @@
 import { IssuePriority } from '../models/enums';
+import { MyDay } from '../models/my-day';
 import { Home } from '../models/home';
 import { PortfolioProject, ProjectInsights } from '../models/insights';
 import {
@@ -157,6 +158,10 @@ export abstract class IssuesGateway {
     note: string | null,
   ): Observable<void>;
   abstract clearReminder(issueId: string): Observable<void>;
+  /** «Mi día» on `day` (today, `YYYY-MM-DD` in my time zone). */
+  abstract myDay(day: string): Observable<MyDay>;
+  abstract addToMyDay(day: string, issueIds: string[]): Observable<void>;
+  abstract removeFromMyDay(day: string, issueId: string): Observable<void>;
   /**
    * Decisions (comments marked as such) of all my projects by their text,
    * most recent first: here and not in CommentsGateway, for the palette.