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/tracker/application/src/lib/releases.service.ts

@@ -70,7 +70,10 @@ export class ReleasesService {
     );
   }
 
-  findOne(viewerId: string, releaseId: string): Promise<ReleaseReadModel> {
+  findOne(
+    viewerId: string | null,
+    releaseId: string,
+  ): Promise<ReleaseReadModel> {
     return this.queryBus.execute(new GetReleaseQuery(viewerId, releaseId));
   }
 
@@ -80,7 +83,7 @@ export class ReleasesService {
   }
 
   progress(
-    viewerId: string,
+    viewerId: string | null,
     releaseId: string,
   ): Promise<ReleaseProgressReadModel> {
     return this.queryBus.execute(
@@ -89,7 +92,10 @@ export class ReleasesService {
   }
 
   /** Scope vs finished tickets of the release, day by day. */
-  burnup(viewerId: string, releaseId: string): Promise<ReleaseBurnupReadModel> {
+  burnup(
+    viewerId: string | null,
+    releaseId: string,
+  ): Promise<ReleaseBurnupReadModel> {
     return this.queryBus.execute(
       new GetReleaseBurnupQuery(viewerId, releaseId),
     );