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/web/tracker/application/src/lib/events/project.events.ts

@@ -51,6 +51,7 @@ export const projectPageEvents = eventGroup({
     analyticsRequested: type<{ projectId: string; days: number }>(),
     burnupRequested: type<{ releaseId: string }>(),
     visibilityChangeRequested: type<{ projectId: string; isPublic: boolean }>(),
+    archiveRequested: type<{ projectId: string; archived: boolean }>(),
     proposalsChangeRequested: type<{
       projectId: string;
       acceptsProposals: boolean;