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/infrastructure/src/lib/mongo/find.repositories.ts

@@ -49,9 +49,10 @@ const FINISHED = [StatusCategory.DONE, StatusCategory.CANCELLED];
 
 function toProject(doc: ProjectDoc): ProjectReadModel {
   const { memberIds: _ignored, ...rest } = doc;
-  // Projects projected before settings existed use the defaults.
+  // Projects projected before settings (or visibility) existed use the defaults.
   return {
     ...fromDoc(rest),
+    isPublic: rest.isPublic ?? false,
     settings: rest.settings ?? defaultProjectSettings(),
   };
 }
@@ -83,6 +84,14 @@ export class MongoFindProjectsRepository extends FindProjectsRepository {
     return docs.map(toProject);
   }
 
+  async findPublic(): Promise<ProjectReadModel[]> {
+    const docs = await this.projects
+      .find({ isPublic: true })
+      .sort({ name: 1 })
+      .lean<ProjectDoc[]>();
+    return docs.map(toProject);
+  }
+
   async findRole(
     projectId: string,
     userId: string,
@@ -207,6 +216,13 @@ export class MongoFindIssuesRepository extends FindIssuesRepository {
     };
   }
 
+  async findOpenAssignedTo(userId: string): Promise<IssueReadModel[]> {
+    const docs = await this.issues
+      .find({ 'assignee.id': userId, statusCategory: { $nin: FINISHED } })
+      .lean<IssueDoc[]>();
+    return docs.map(issueFromDoc);
+  }
+
   async findByProject(projectId: string): Promise<IssueReadModel[]> {
     const docs = await this.issues.find({ projectId }).lean<IssueDoc[]>();
     return docs.map(issueFromDoc);