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/postgres/tracker-streams.repository.ts

@@ -0,0 +1,62 @@
+import { Injectable } from '@nestjs/common';
+import { TrackerStreamsRepository } from '@task-stream/api/tracker/application';
+import {
+  CommentAddedEvent,
+  IssueCreatedEvent,
+  IssueLinkedEvent,
+  ReleaseCreatedEvent,
+} from '@task-stream/api/tracker/domain';
+import { DataSource } from 'typeorm';
+
+/** Reads the event store directly: which streams hang off a project or a ticket. */
+@Injectable()
+export class PostgresTrackerStreamsRepository extends TrackerStreamsRepository {
+  constructor(private readonly dataSource: DataSource) {
+    super();
+  }
+
+  issueIdsOfProject(projectId: string): Promise<string[]> {
+    return this.streams(
+      IssueCreatedEvent.name,
+      `data->>'projectId'`,
+      projectId,
+    );
+  }
+
+  releaseIdsOfProject(projectId: string): Promise<string[]> {
+    return this.streams(
+      ReleaseCreatedEvent.name,
+      `data->>'projectId'`,
+      projectId,
+    );
+  }
+
+  commentIdsOfIssue(issueId: string): Promise<string[]> {
+    return this.streams(
+      CommentAddedEvent.name,
+      `data->'comment'->>'issueId'`,
+      issueId,
+    );
+  }
+
+  issueIdsLinkingTo(issueId: string): Promise<string[]> {
+    return this.streams(
+      IssueLinkedEvent.name,
+      `data->'link'->>'targetIssueId'`,
+      issueId,
+    );
+  }
+
+  /** `field` is one of the fixed JSON paths above, never user input. */
+  private async streams(
+    type: string,
+    field: string,
+    value: string,
+  ): Promise<string[]> {
+    const rows: { stream_id: string }[] = await this.dataSource.query(
+      `SELECT DISTINCT stream_id FROM events WHERE type = $1 AND ${field} = $2`,
+      [type, value],
+    );
+    return rows.map((row) => row.stream_id);
+  }
+}