feat: guest role for clients and outsiders

A project member can be a GUEST. In a private project a guest only sees
the tickets they take part in (opened, assigned or followed): every other
ticket answers 404, also in my work, realtime changes, blockers and
linked tickets, and project-wide views (activity, statistics, dashboard,
releases, sprints, epics, trash) answer 403. Guests open tickets without
assigning or planning them, and comment, attach, follow and vote on their
own; they change nothing else. In a public project they see what anyone
does. The web gives them only Tablero, Lista and Miembros and loads none
of the project-wide data.

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

apps/mcp/src/app/api/taskstream.schema.ts

@@ -1721,7 +1721,7 @@ export interface components {
             name: string;
         };
         /** @enum {string} */
-        ProjectRole: "OWNER" | "ADMIN" | "MEMBER" | "VIEWER";
+        ProjectRole: "OWNER" | "ADMIN" | "MEMBER" | "VIEWER" | "GUEST";
         ProjectMemberDto: {
             user: components["schemas"]["UserRefDto"];
             role: components["schemas"]["ProjectRole"];