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/infrastructure/src/lib/adapters/graphql-projects.gateway.ts

@@ -17,6 +17,8 @@ import {
   ChangeProjectMemberRoleDocument,
   CreateProjectDocument,
   DeleteProjectDocument,
+  ArchiveProjectDocument,
+  UnarchiveProjectDocument,
   MyProjectsDocument,
   ProjectAnalyticsDocument,
   ProjectInsightsDocument,
@@ -102,6 +104,16 @@ export class GraphqlProjectsGateway extends ProjectsGateway {
       .pipe(map((d) => toCommandResult(d.updateProject)));
   }
 
+  setArchived(projectId: string, archived: boolean): Observable<CommandResult> {
+    return archived
+      ? this.gql
+          .mutate(ArchiveProjectDocument, { projectId })
+          .pipe(map((d) => toCommandResult(d.archiveProject)))
+      : this.gql
+          .mutate(UnarchiveProjectDocument, { projectId })
+          .pipe(map((d) => toCommandResult(d.unarchiveProject)));
+  }
+
   delete(projectId: string, confirmKey: string): Observable<CommandResult> {
     return this.gql
       .mutate(DeleteProjectDocument, { projectId, confirmKey })