feat: public projects, project deletion and sagas

Public projects:
- Project.isPublic (create/update, owners and admins). Anyone can read a
  public project without a token: project, board, tickets, comments,
  history, releases, activity, tracking and statistics, over GraphQL and
  REST. Writes stay for members (401 anonymous, 403 outsiders).
- @OptionalAuth() / @ApiOptionalPireonAuth(): anonymous callers allowed,
  invalid tokens still rejected. ReadAccess lets anonymous viewers read
  public projects only; linked tickets are filtered by visibility.
- publicProjects (GraphQL) and GET /api/explore/projects (REST).
- Web: «Explorar» page, project pages open without a session (read-only
  notice, sign-in hints), public badge, visibility switch in settings,
  no realtime subscriptions without a session.

Project deletion:
- Owner only, confirming the key (deleteProject / DELETE
  /api/projects/{project}?confirm=KEY). The key is freed; the read model
  drops the project and members are notified (web goes home).

Sagas (run by the EventsBridge after projections, durable and ordered):
- ProjectDeletionSaga: project deleted → delete its tickets and releases;
  ticket deleted → purge its comments and drop links from other tickets.
- ReleaseArchivedSaga: unfinished tickets leave an archived release.
- UserDeactivatedSaga: the Pireon webhook records UserDeactivatedEvent in
  the event store (EventRecorder); the tracker unassigns that user's open
  tickets as the system actor.
- Internal idempotent commands; domain refusals are logged and skipped,
  concurrency conflicts retried. Affected streams come from the event store
  (TrackerStreamsRepository).

Tests: domain lifecycle specs, saga specs run like the bridge, facade
tests, e2e for public access, cascade deletion, archived releases and
deactivation webhook. Docs, READMEs, schema.gql/openapi.json and Word/PDF
updated.

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

libs/api/shared/infrastructure/README.md

@@ -10,7 +10,8 @@ Event store en PostgreSQL y el camino de los eventos hasta la lectura.
 - `PostgresEventStore` (tabla `events`, `UNIQUE(stream_id, position)` → `ConcurrencyError`).
 - `EventSerializer` / `EventDeserializer` y `EventStorePublisher` (sustituye al publisher del `EventBus`: `commit()` persiste).
 - `EventStoreRelay`: copia los eventos nuevos al Redis Stream (`FOR UPDATE SKIP LOCKED`).
-- `EventsBridge`: consume el stream y entrega cada evento a sus `@EventsHandler`, en orden y esperando (ACK al final).
+- `EventsBridge`: consume el stream y entrega cada evento a sus `@EventsHandler`, en orden y esperando (ACK al final);
+  después ejecuta los `@Saga()` (el `EventBus` en memoria nunca ve los eventos guardados) y sus comandos, uno a uno.
 - Conexiones Redis (`REDIS_CLIENT`, `GRAPHQL_PUB_SUB`) y `SharedInfrastructureModule.forRootAsync`.
 
 Flujo completo: [Arquitectura](../../../../docs/02-arquitectura.md#22-flujo-completo-de-una-escritura).