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>

apps/api/e2e/tracker.e2e-spec.ts

@@ -1567,4 +1567,78 @@ describe('task-stream (e2e)', () => {
       ).status,
     ).toBe(200);
   });
+
+  it('archives a project: readable, read-only, back on demand', async () => {
+    const key = 'A' + Date.now().toString(36).slice(-5).toUpperCase();
+    await rest('token-ana', 'POST', '/projects', { key, name: key });
+    await eventually(
+      () => rest('token-ana', 'GET', `/projects/${key}`),
+      (r) => r.status === 200,
+    );
+    const added = await rest('token-ana', 'POST', `/projects/${key}/members`, {
+      userId: '102',
+    });
+    expect(added.status).toBe(201);
+    await eventually(
+      () => rest('token-bob', 'GET', `/projects/${key}`),
+      (r) => r.status === 200,
+    );
+    const created = await rest('token-bob', 'POST', `/projects/${key}/issues`, {
+      type: 'TASK',
+      title: 'Antes de archivar',
+    });
+    expect(created.body).toMatchObject({ key: `${key}-1` });
+    const ticket = created.body['key'] as string;
+    await eventually(
+      () => rest('token-bob', 'GET', `/issues/${ticket}`),
+      (r) => r.status === 200,
+    );
+
+    expect(
+      (await rest('token-bob', 'POST', `/projects/${key}/archive`)).status,
+    ).toBe(403);
+    expect(
+      (await rest('token-ana', 'POST', `/projects/${key}/archive`)).status,
+    ).toBe(200);
+    const archived = await eventually(
+      () => rest('token-bob', 'GET', `/projects/${key}`),
+      (r) => !!r.body['archivedAt'],
+    );
+    expect(archived.status).toBe(200);
+    // Still readable; nothing changes.
+    expect((await rest('token-bob', 'GET', `/issues/${ticket}`)).status).toBe(
+      200,
+    );
+    const refused = await rest('token-bob', 'PATCH', `/issues/${ticket}`, {
+      title: 'Después',
+    });
+    expect(refused.status).toBe(422);
+    expect(refused.body['message']).toMatch(/archivado/);
+    expect(
+      (
+        await rest('token-bob', 'POST', `/projects/${key}/issues`, {
+          type: 'TASK',
+          title: 'Nuevo',
+        })
+      ).status,
+    ).toBe(422);
+
+    const { unarchiveProject } = await gql(
+      'token-ana',
+      `mutation($p: ID!) { unarchiveProject(projectId: $p) { version } }`,
+      { p: archived.body['id'] },
+    );
+    expect(unarchiveProject.version).toBeGreaterThan(0);
+    await eventually(
+      () => rest('token-bob', 'GET', `/projects/${key}`),
+      (r) => r.body['archivedAt'] === null,
+    );
+    expect(
+      (
+        await rest('token-bob', 'PATCH', `/issues/${ticket}`, {
+          title: 'Después',
+        })
+      ).status,
+    ).toBe(200);
+  });
 });