feat: «Recordármelo», a reminder of a ticket only for me

On a ticket, «Recordármelo» offers in an hour, this evening, tomorrow or
next Monday at 9, in a week, or any date and time, with an optional note.
The ticket shows the waiting one («Te lo recordaré el mié 21 a las 9:00»)
to change or drop. Every minute a scheduler tells the ones whose time
came as a REMINDER notification (bell, push, e-mail), once, and forgets
those whose ticket went to the trash or out of reach. One per person and
ticket, private, no history (Mongo `issue_reminders`).

API: setReminder / clearReminder, Issue.myReminder, myReminders;
PUT/DELETE /api/issues/{issue}/reminder, GET /api/me/reminders. MCP:
remind_me.

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

libs/web/tracker/domain/src/index.ts

@@ -1,6 +1,7 @@
 export * from './lib/models/enums';
 export * from './lib/models/models';
 export * from './lib/models/bulk';
+export * from './lib/models/reminders';
 export * from './lib/models/inputs';
 export * from './lib/models/workflow';
 export * from './lib/ports/gateways';

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

@@ -196,6 +196,8 @@ export interface Issue extends IssueSummary {
   pinned: boolean;
   /** Whether I follow it with everything under it (an epic). */
   followingTree: boolean;
+  /** My waiting reminder on it («remind me on Thursday»). */
+  myReminder: IssueReminder | null;
   /** Its comments marked as decisions, oldest first. */
   decisions: Comment[];
   checklist: ChecklistItem[];
@@ -206,6 +208,13 @@ export interface Issue extends IssueSummary {
 }
 
 /** Someone else on a ticket's page right now. */
+/** My own reminder on a ticket. */
+export interface IssueReminder {
+  /** ISO date-time. */
+  at: string;
+  note: string | null;
+}
+
 /** Someone writing on a ticket right now. */
 export interface Typing {
   user: UserRef;

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

@@ -0,0 +1,40 @@
+import { reminderChoices } from './reminders';
+
+const local = (y: number, m: number, d: number, h: number, min = 0) =>
+  new Date(y, m - 1, d, h, min);
+
+describe('reminder choices', () => {
+  it('offers this evening only while there is time', () => {
+    // Tuesday 20 October 2026.
+    const morning = reminderChoices(local(2026, 10, 20, 10)).map(
+      (c) => c.label,
+    );
+    expect(morning).toEqual([
+      'Dentro de 1 hora',
+      'Esta tarde, a las 18:00',
+      'Mañana a las 9:00',
+      'El lunes a las 9:00',
+      'Dentro de una semana',
+    ]);
+    const late = reminderChoices(local(2026, 10, 20, 19)).map((c) => c.label);
+    expect(late).not.toContain('Esta tarde, a las 18:00');
+  });
+
+  it('lands on the right days and hours, local time', () => {
+    const [, evening, tomorrow, monday, week] = reminderChoices(
+      local(2026, 10, 20, 10, 30),
+    ).map((c) => new Date(c.at));
+    expect([evening.getDate(), evening.getHours()]).toEqual([20, 18]);
+    expect([tomorrow.getDate(), tomorrow.getHours()]).toEqual([21, 9]);
+    expect([monday.getDay(), monday.getDate(), monday.getHours()]).toEqual([
+      1, 26, 9,
+    ]);
+    expect([week.getDate(), week.getHours()]).toEqual([27, 9]);
+  });
+
+  it('does not offer Monday twice on a Sunday (it is tomorrow)', () => {
+    const sunday = reminderChoices(local(2026, 10, 25, 10)).map((c) => c.label);
+    expect(sunday.filter((l) => l.includes('lunes'))).toEqual([]);
+    expect(sunday).toContain('Mañana a las 9:00');
+  });
+});

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

@@ -0,0 +1,48 @@
+/** A ready-made moment for «remind me…». */
+export interface ReminderChoice {
+  label: string;
+  /** ISO date-time. */
+  at: string;
+}
+
+/** «el jue 23 a las 9:00», in the browser's time zone. */
+export function whenLabel(at: string): string {
+  const date = new Date(at);
+  const day = date.toLocaleDateString('es', {
+    weekday: 'short',
+    day: 'numeric',
+    month: 'short',
+  });
+  const time = date.toLocaleTimeString('es', {
+    hour: '2-digit',
+    minute: '2-digit',
+  });
+  return `el ${day} a las ${time}`;
+}
+
+/** `now` moved `days` days on, at `hour`:00 (local time). */
+function at(now: Date, days: number, hour: number): Date {
+  const date = new Date(now);
+  date.setDate(date.getDate() + days);
+  date.setHours(hour, 0, 0, 0);
+  return date;
+}
+
+/**
+ * The usual moments, from `now` in local time: in an hour, this evening
+ * (while there is time), tomorrow and next Monday at 9, and in a week.
+ */
+export function reminderChoices(now: Date = new Date()): ReminderChoice[] {
+  const choices: { label: string; at: Date }[] = [
+    { label: 'Dentro de 1 hora', at: new Date(now.getTime() + 3_600_000) },
+  ];
+  if (now.getHours() < 17)
+    choices.push({ label: 'Esta tarde, a las 18:00', at: at(now, 0, 18) });
+  choices.push({ label: 'Mañana a las 9:00', at: at(now, 1, 9) });
+  // Monday is 1; from Sunday it is tomorrow, from Monday next week.
+  const toMonday = (8 - now.getDay()) % 7 || 7;
+  if (toMonday > 1)
+    choices.push({ label: 'El lunes a las 9:00', at: at(now, toMonday, 9) });
+  choices.push({ label: 'Dentro de una semana', at: at(now, 7, 9) });
+  return choices.map((c) => ({ label: c.label, at: c.at.toISOString() }));
+}

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

@@ -150,6 +150,13 @@ export abstract class IssuesGateway {
   abstract pin(issueId: string, pinned: boolean): Observable<void>;
   /** Follows the ticket with everything under it (or stops). */
   abstract followTree(issueId: string, on: boolean): Observable<void>;
+  /** Reminds me of the ticket then (replaces the waiting one). */
+  abstract setReminder(
+    issueId: string,
+    at: string,
+    note: string | null,
+  ): Observable<void>;
+  abstract clearReminder(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.