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/domain/src/lib/events/index.ts

@@ -19,3 +19,6 @@ export * from './release-created.event';
 export * from './release-updated.event';
 export * from './release-shipped.event';
 export * from './release-archived.event';
+export * from './project-deleted.event';
+export * from './issue-deleted.event';
+export * from './release-deleted.event';

libs/api/tracker/domain/src/lib/events/issue-deleted.event.ts

@@ -0,0 +1,15 @@
+import { AutowiredEvent } from '@task-stream/api/shared/domain';
+import { TrackerEvent } from './tracker.event';
+
+/** The ticket was deleted (its project was). Its comments and the links to it go next. */
+@AutowiredEvent
+export class IssueDeletedEvent extends TrackerEvent {
+  constructor(
+    actorId: string,
+    issueId: string,
+    projectId: string,
+    readonly key: string,
+  ) {
+    super(actorId, issueId, projectId);
+  }
+}

libs/api/tracker/domain/src/lib/events/project-deleted.event.ts

@@ -0,0 +1,19 @@
+import { AutowiredEvent } from '@task-stream/api/shared/domain';
+import { TrackerEvent } from './tracker.event';
+
+/**
+ * The owner deleted the project. Its tickets and releases are deleted next by
+ * the cascade saga; the key becomes free again.
+ */
+@AutowiredEvent
+export class ProjectDeletedEvent extends TrackerEvent {
+  constructor(
+    actorId: string,
+    projectId: string,
+    readonly key: string,
+    /** Members at the time, so their project lists drop it. */
+    readonly memberIds: string[],
+  ) {
+    super(actorId, projectId, projectId);
+  }
+}

libs/api/tracker/domain/src/lib/events/project-updated.event.ts

@@ -2,13 +2,15 @@ import { AutowiredEvent } from '@task-stream/api/shared/domain';
 import type { ProjectProps } from '../project/project';
 import { TrackerEvent } from './tracker.event';
 
-/** Name or description changed. */
+/** Name, description or visibility changed. */
 @AutowiredEvent
 export class ProjectUpdatedEvent extends TrackerEvent {
   constructor(
     actorId: string,
     projectId: string,
-    readonly changes: Partial<Pick<ProjectProps, 'name' | 'description'>>,
+    readonly changes: Partial<
+      Pick<ProjectProps, 'name' | 'description' | 'isPublic'>
+    >,
   ) {
     super(actorId, projectId, projectId);
   }

libs/api/tracker/domain/src/lib/events/release-deleted.event.ts

@@ -0,0 +1,10 @@
+import { AutowiredEvent } from '@task-stream/api/shared/domain';
+import { TrackerEvent } from './tracker.event';
+
+/** The release was deleted (its project was). */
+@AutowiredEvent
+export class ReleaseDeletedEvent extends TrackerEvent {
+  constructor(actorId: string, releaseId: string, projectId: string) {
+    super(actorId, releaseId, projectId);
+  }
+}