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/identity/application/src/lib/commands/handle-identity-webhook.command.ts

@@ -1,5 +1,7 @@
 import { Logger } from '@nestjs/common';
 import { Command, CommandHandler, ICommandHandler } from '@nestjs/cqrs';
+import { EventRecorder } from '@task-stream/api/shared/application';
+import { UserDeactivatedEvent } from '@task-stream/api/identity/domain';
 import { SessionCache } from '../ports/session-cache.port';
 import { UserRegistry } from '../ports/user-registry.port';
 
@@ -22,6 +24,7 @@ export class HandleIdentityWebhookHandler
   constructor(
     private readonly cache: SessionCache,
     private readonly registry: UserRegistry,
+    private readonly events: EventRecorder,
   ) {}
 
   async execute({ event, data }: HandleIdentityWebhookCommand): Promise<void> {
@@ -50,8 +53,14 @@ export class HandleIdentityWebhookHandler
 
   private async deactivate(userId: string): Promise<void> {
     const user = await this.registry.findById(userId);
-    if (!user) return;
+    if (!user?.isActive) return;
     user.deactivate();
     await this.registry.upsert(user);
+    // Stored so other contexts react (the tracker unassigns their open tickets).
+    for (const event of user.getUncommittedEvents()) {
+      if (event instanceof UserDeactivatedEvent)
+        await this.events.record(`identity-user-${userId}`, event);
+    }
+    user.uncommit();
   }
 }