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/web/tracker/application/src/lib/events/explore.events.ts

@@ -0,0 +1,18 @@
+import { type } from '@ngrx/signals';
+import { eventGroup } from '@ngrx/signals/events';
+import { Project } from '@task-stream/web/tracker/domain';
+
+export const explorePageEvents = eventGroup({
+  source: 'Explore Page',
+  events: {
+    opened: type<void>(),
+  },
+});
+
+export const exploreApiEvents = eventGroup({
+  source: 'Explore API',
+  events: {
+    loaded: type<Project[]>(),
+    loadFailed: type<string>(),
+  },
+});

libs/web/tracker/application/src/lib/events/project.events.ts

@@ -30,6 +30,8 @@ export const projectPageEvents = eventGroup({
     }>(),
     analyticsRequested: type<{ projectId: string; days: number }>(),
     burnupRequested: type<{ releaseId: string }>(),
+    visibilityChangeRequested: type<{ projectId: string; isPublic: boolean }>(),
+    deleteRequested: type<{ projectId: string; confirmKey: string }>(),
   },
 });
 
@@ -48,6 +50,8 @@ export const projectApiEvents = eventGroup({
     analyticsFailed: type<string>(),
     burnupLoaded: type<ReleaseBurnup>(),
     settingsSaved: type<string>(),
+    /** I deleted the open project. */
+    deleted: type<string>(),
   },
 });
 
@@ -55,6 +59,8 @@ export const projectRealtimeEvents = eventGroup({
   source: 'Project Realtime',
   events: {
     projectChanged: type<Project>(),
+    /** Someone else deleted the open project. */
+    projectDeleted: type<Project>(),
     activityAdded: type<Activity>(),
     releaseChanged: type<Release>(),
   },