feat: sprints with burndown and carry-over

Plan sprints with dates and a goal, run one at a time per project, and
put tickets in them from the ticket page. The Sprints tab follows the one
under way with its progress and a burndown in tickets or points against
the ideal line. Closing a sprint sends what was left to the next one or
back to the backlog; the board can be filtered by sprint.

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

libs/web/tracker/presenters/src/lib/pages/board.page.ts

@@ -137,6 +137,12 @@ const NOBODY = '__nobody__';
         [options]="priorityFilterOptions"
         [(value)]="priorityFilter"
       />
+      <pi-select-field
+        class="ts-filter"
+        placeholder="Sprint"
+        [options]="sprintFilterOptions()"
+        [(value)]="sprintFilter"
+      />
       <pi-select-field
         class="ts-filter"
         placeholder="Release"
@@ -335,6 +341,8 @@ export class BoardPage {
   readonly release = input<string | undefined>();
   /** `?assignee=` (from the tracking page's team list), bound by the router. */
   readonly assignee = input<string | undefined>();
+  /** `?sprint=` (from the sprints page), bound by the router. */
+  readonly sprint = input<string | undefined>();
 
   protected readonly board = inject(BoardFacade);
   protected readonly project = inject(ProjectFacade);
@@ -353,6 +361,16 @@ export class BoardPage {
   protected readonly releaseFilter = signal<string | null>(ALL);
   protected readonly area = signal<string | null>(ALL);
   protected readonly typeFilter = signal<string | null>(ALL);
+  protected readonly sprintFilter = signal<string | null>(ALL);
+  protected readonly sprintFilterOptions = computed<
+    PiSelectFieldOption<string>[]
+  >(() => [
+    { value: ALL, label: 'Todos los sprints' },
+    ...this.project.openSprints().map((s) => ({
+      value: s.id,
+      label: s.status === 'ACTIVE' ? `${s.name} · en curso` : s.name,
+    })),
+  ]);
   protected readonly priorityFilter = signal<string | null>(ALL);
   /** What is typed; `search` follows it once typing pauses. */
   protected readonly searchInput = signal('');
@@ -364,6 +382,7 @@ export class BoardPage {
       !!(
         this.assigneeFilter() ||
         this.releaseFilter() ||
+        this.sprintFilter() ||
         this.area() ||
         this.typeFilter() ||
         this.priorityFilter() ||
@@ -485,6 +504,10 @@ export class BoardPage {
       const assignee = this.assignee();
       if (assignee) untracked(() => this.assigneeFilter.set(assignee));
     });
+    effect(() => {
+      const sprint = this.sprint();
+      if (sprint) untracked(() => this.sprintFilter.set(sprint));
+    });
     effect((onCleanup) => {
       const text = this.searchInput().trim();
       const timer = setTimeout(() => this.search.set(text), 300);
@@ -505,6 +528,7 @@ export class BoardPage {
         priorities: priority ? [priority] : undefined,
         labels: this.labels().length ? this.labels() : undefined,
         search: this.search() || undefined,
+        sprintId: this.sprintFilter() || undefined,
       };
       if (!projectId) return;
       untracked(() =>
@@ -569,6 +593,7 @@ export class BoardPage {
       filter.unassigned ? NOBODY : (filter.assigneeId ?? ALL),
     );
     this.releaseFilter.set(filter.releaseId ?? ALL);
+    this.sprintFilter.set(ALL);
     this.area.set(filter.area ?? ALL);
     this.typeFilter.set(filter.types?.[0] ?? ALL);
     this.priorityFilter.set(filter.priorities?.[0] ?? ALL);
@@ -581,6 +606,7 @@ export class BoardPage {
     for (const filter of [
       this.assigneeFilter,
       this.releaseFilter,
+      this.sprintFilter,
       this.area,
       this.typeFilter,
       this.priorityFilter,