feat: due-date reminders

Every hour the API reminds whoever has a ticket, and whoever follows it,
the day before its due date, on the day and once when it is overdue, in
the app and by e-mail for those who asked. Cards on the board flag what
is due soon or late.

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

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

@@ -10,3 +10,4 @@ export * from './lib/models/estimation';
 export * from './lib/models/swimlanes';
 export * from './lib/models/roadmap';
 export * from './lib/models/shortcuts';
+export * from './lib/models/due';

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

@@ -0,0 +1,16 @@
+import { StatusCategory } from './enums';
+import { dueState } from './due';
+
+describe('due state', () => {
+  const today = '2026-10-08';
+  it('flags late, today and the next two days, never finished tickets', () => {
+    expect(dueState('2026-10-07', StatusCategory.TODO, today)).toBe('overdue');
+    expect(dueState('2026-10-08', StatusCategory.IN_PROGRESS, today)).toBe(
+      'today',
+    );
+    expect(dueState('2026-10-10', StatusCategory.QA, today)).toBe('soon');
+    expect(dueState('2026-10-11', StatusCategory.TODO, today)).toBeNull();
+    expect(dueState('2026-10-01', StatusCategory.DONE, today)).toBeNull();
+    expect(dueState(null, StatusCategory.TODO, today)).toBeNull();
+  });
+});

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

@@ -0,0 +1,27 @@
+import { StatusCategory } from './enums';
+
+export type DueState = 'overdue' | 'today' | 'soon' | null;
+
+/** `YYYY-MM-DD` of a local date. */
+export function localDay(date: Date): string {
+  return `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, '0')}-${String(date.getDate()).padStart(2, '0')}`;
+}
+
+/**
+ * How urgent a due date looks: overdue, today, or within the next two days.
+ * Finished tickets are never late.
+ */
+export function dueState(
+  dueDate: string | null,
+  category: StatusCategory,
+  today = localDay(new Date()),
+): DueState {
+  if (!dueDate) return null;
+  if (category === StatusCategory.DONE || category === StatusCategory.CANCELLED)
+    return null;
+  const due = dueDate.slice(0, 10);
+  if (due < today) return 'overdue';
+  if (due === today) return 'today';
+  const days = (Date.parse(due) - Date.parse(today)) / 86_400_000;
+  return days <= 2 ? 'soon' : null;
+}

libs/web/tracker/presenters/src/lib/ui/issue-card.ts

@@ -6,7 +6,12 @@ import {
 } from '@angular/core';
 import { RouterLink } from '@angular/router';
 import { PiIconComponent } from '@pi/ui';
-import { IssueSummary, Workflow } from '@task-stream/web/tracker/domain';
+import {
+  DueState,
+  dueState,
+  IssueSummary,
+  Workflow,
+} from '@task-stream/web/tracker/domain';
 import { initials, PRIORITY, PRIORITY_LEVEL, typeLook } from './copy';
 
 /** A ticket on the board / in lists: type stripe, key, title, signals. */
@@ -45,6 +50,14 @@ import { initials, PRIORITY, PRIORITY_LEVEL, typeLook } from './copy';
             >↑ {{ parent.key }}</span
           >
         }
+        @if (due(); as state) {
+          <span
+            class="ts-card__due"
+            [attr.data-due]="state"
+            [attr.title]="'Fecha límite: ' + issue().dueDate"
+            >{{ dueLabel(state) }}</span
+          >
+        }
         @if (issue().storyPoints !== null) {
           <span class="ts-card__points" title="Estimación">{{
             issue().storyPoints
@@ -78,6 +91,25 @@ import { initials, PRIORITY, PRIORITY_LEVEL, typeLook } from './copy';
     :host {
       display: block;
     }
+    .ts-card__due {
+      padding: 0 0.375rem;
+      border-radius: 999px;
+      font-size: 0.6875rem;
+      font-weight: 600;
+      background: color-mix(
+        in srgb,
+        var(--ts-c-amber, #d97706) 18%,
+        transparent
+      );
+      &[data-due='overdue'] {
+        background: color-mix(
+          in srgb,
+          var(--ts-c-red, #dc2626) 18%,
+          transparent
+        );
+        color: var(--ts-c-red, inherit);
+      }
+    }
     .ts-card__points {
       display: inline-grid;
       place-items: center;
@@ -227,6 +259,16 @@ import { initials, PRIORITY, PRIORITY_LEVEL, typeLook } from './copy';
   `,
 })
 export class IssueCardComponent {
+  /** Late, due today or in the next two days. */
+  protected readonly due = computed(() =>
+    dueState(this.issue().dueDate, this.issue().statusCategory),
+  );
+  protected dueLabel(state: DueState): string {
+    if (state === 'overdue') return 'Vencido';
+    if (state === 'today') return 'Vence hoy';
+    const day = new Date(`${this.issue().dueDate?.slice(0, 10)}T00:00:00`);
+    return day.toLocaleDateString('es', { day: 'numeric', month: 'short' });
+  }
   readonly issue = input.required<IssueSummary>();
   /** The project's settings: names, icons and colours of types and areas. */
   readonly workflow = input.required<Workflow>();