feat: archive a project instead of deleting it

The owner archives a finished project (archiveProject, POST
/projects/{project}/archive) and brings it back (unarchive). While
archived it stays readable, managers still read its rules and webhooks,
but no command changes it: contributing and managing checks refuse with
422, votes and public proposals too, and automations do not run. The web
shows a read-only notice on every page of it (with «Desarchivar» for the
owner), hides what edits, marks it on the home page and lists it last.

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

libs/api/tracker/domain/src/lib/events/index.ts

@@ -21,6 +21,7 @@ export * from './release-updated.event';
 export * from './release-shipped.event';
 export * from './release-archived.event';
 export * from './project-deleted.event';
+export * from './project-archived.event';
 export * from './issue-deleted.event';
 export * from './release-deleted.event';
 export * from './issue-attachment-added.event';