feat(api): expose async backup/restore job status (fixes #7)

Backup and restore only enqueue a cluster Job; a later failure left its
only trace in that Job object, invisible without kubectl. Add
GET /api/v1/servers/{name}/jobs (owner-or-admin) projecting the newest
20 managed Jobs (felis-backup / felis-restore) as
running|succeeded|failed with message and timestamps. Nil reader -> 503
jobs_unavailable, mirroring the backup/restore feature gates. RBAC gains
jobs:list; OpenAPI parity updated.

internal/platform/rbac_test.go

@@ -73,7 +73,7 @@ func TestAPIRole_CreatesJobsInBothNamespaces(t *testing.T) {
 	if mc.Namespace != "minecraft" {
 		t.Errorf("felis-api minecraft Role namespace = %q, want minecraft", mc.Namespace)
 	}
-	for _, v := range []string{"create", "get", "delete"} {
+	for _, v := range []string{"create", "get", "delete", "list"} {
 		if !hasRule(mc, "batch", "jobs", v) {
 			t.Errorf("felis-api (minecraft) must have batch/jobs:%s for the restore-Job lifecycle", v)
 		}