feat: a public notes page per release, for clients

On the releases page, «Página pública» (owners and admins) opens a
secret link to a page with the release's notes, readable without an
account, also for private projects: the notes written, or the draft
from its finished tickets while there are none (without repeating the
title the page already shows). The link can be copied, renewed (the old
one stops working) or withdrawn. Stored in Mongo (`release_note_shares`).

API: shareReleaseNotes / unshareReleaseNotes / releaseNotesShare,
publicReleaseNotes(token); GET/PUT/DELETE /api/releases/{id}/public-notes,
GET /api/shared/release-notes/{token}. Web: /notes/:token.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/web/tracker/domain/src/lib/ports/gateways.ts

@@ -4,6 +4,8 @@ import { Home } from '../models/home';
 import { PortfolioProject, ProjectInsights } from '../models/insights';
 import {
   DashboardShare,
+  PublicReleaseNotes,
+  ReleaseNotesShare,
   SharedBlock,
   SharedDashboard,
 } from '../models/sharing';
@@ -474,6 +476,20 @@ export abstract class SharingGateway {
   abstract remove(projectId: string): Observable<void>;
   /** What a link shows, for anyone (null: no such link). */
   abstract shared(token: string): Observable<SharedDashboard | null>;
+  /** A release's public notes link, if any (owners and admins). */
+  abstract releaseNotesShare(
+    releaseId: string,
+  ): Observable<ReleaseNotesShare | null>;
+  /** Turns it on; `renew` makes a new link. */
+  abstract shareReleaseNotes(
+    releaseId: string,
+    renew: boolean,
+  ): Observable<ReleaseNotesShare>;
+  abstract unshareReleaseNotes(releaseId: string): Observable<void>;
+  /** A release's notes for anyone with the link (null: no such link). */
+  abstract publicReleaseNotes(
+    token: string,
+  ): Observable<PublicReleaseNotes | null>;
 }
 
 export abstract class NotificationsGateway {