fix(install): backups exist on a default install; retention resolves real world dirs (#6)

Three faces of one gap, all on the supported install path:

- Backup/restore answered 503 out of the box: nothing ever rendered the
  archive PVC, so FELIS_BACKUP_PVC was unset. The bundle now renders the
  PVC (Minecraft namespace, RWO 10Gi, cluster default class) and
  'felis manifests' names it by default (--backup-pvc= is the explicit
  no-store shape); bootstrap passes it through so the generated felis.toml
  [archive] local_path and the jobs' mount path come from one variable.
- Retention was unreachable: bootstrap never passed the reaper flags. It
  now forwards FELIS_WORLDS_HOST_PATH/FELIS_ARCHIVE_LOCAL_PATH, so one
  env enables the daily CronJob; unset keeps today's fail-safe (no reaper,
  nothing deleted).
- Even when enabled it could not find a world on a stock install:
  resolveWorldDir now also resolves the exact local-path directory
  <pv-name>_<ns>_<pvc-name> read from the live PVC's volumeName (never a
  glob, so a stale deleted PV's bytes can't be archived in place of the
  current world). Reaper Role gains persistentvolumeclaims:get (weaker
  than the delete it already held).

README (zh/en) stops promising automatic/scheduled backups and states
retention is opt-in. bootstrap_test covers the env->flag contract.

cmd/felis/manifests_test.go

@@ -77,6 +77,10 @@ func TestManifestsRendersBundle(t *testing.T) {
 		"10.0.0.5/32",
 		// The felis image flows through to the Deployments.
 		"registry.felis.svc:5000/felis:v1",
+		// Backup works out of the box: the archive PVC renders and the api gets
+		// the env that wires the backup/restore executors to it.
+		"name: felis-backups",
+		"name: FELIS_BACKUP_PVC",
 	} {
 		if !strings.Contains(text, want) {
 			t.Errorf("rendered bundle missing %q", want)
@@ -95,15 +99,19 @@ func TestManifestsRendersBundle(t *testing.T) {
 	}
 }
 
-// TestManifestsReaperRequiresTrio proves --worlds-host-path is a fail-loud opt-in:
-// asking for the reaper without the backup PVC and its mount path (which must equal
-// [archive] local_path) is rejected rather than silently dropping retention.
-func TestManifestsReaperRequiresTrio(t *testing.T) {
+// TestManifestsReaperRequiresStorage proves --worlds-host-path is a fail-loud
+// opt-in: asking for the reaper without a writable archive store (the backup PVC,
+// which defaults to felis-backups but can be emptied) and its mount path (which
+// must equal [archive] local_path) is rejected rather than silently dropping
+// retention or deleting worlds it could not archive first.
+func TestManifestsReaperRequiresStorage(t *testing.T) {
 	base := []string{"manifests", "--felis-image", "reg/felis:test", "--velocity-cidr", "10.0.0.5/32", "--worlds-host-path", "/var/lib/felis/worlds"}
 	for _, extra := range [][]string{
-		{},                                   // neither backup-pvc nor archive-local-path
-		{"--backup-pvc", "felis-backups"},    // missing archive-local-path
-		{"--archive-local-path", "/backups"}, // missing backup-pvc
+		{},                        // missing archive-local-path (backup-pvc defaults)
+		{"--backup-pvc", "other"}, // still missing archive-local-path
+		// A reaper with no archive store would have nowhere to write the archive
+		// it must verify before deleting a world; emptying the PVC is rejected.
+		{"--archive-local-path", "/backups", "--backup-pvc="},
 	} {
 		var out, errBuf bytes.Buffer
 		code := run(append(append([]string{}, base...), extra...), &out, &errBuf)
@@ -119,6 +127,23 @@ func TestManifestsReaperRequiresTrio(t *testing.T) {
 	}
 }
 
+// TestManifestsBackupPVCOptOut proves --backup-pvc= renders a bundle with no
+// archive store at all: no PVC and no FELIS_BACKUP_PVC env, so backup/restore
+// answer 503 instead of pointing Jobs at a claim nobody provisions.
+func TestManifestsBackupPVCOptOut(t *testing.T) {
+	var out, errBuf bytes.Buffer
+	code := run([]string{"manifests", "--felis-image", "reg/felis:test",
+		"--velocity-cidr", "10.0.0.5/32", "--backup-pvc="}, &out, &errBuf)
+	if code != 0 {
+		t.Fatalf("exit code = %d, want 0; stderr=%q", code, errBuf.String())
+	}
+	for _, absent := range []string{"felis-backups", "FELIS_BACKUP_PVC"} {
+		if strings.Contains(out.String(), absent) {
+			t.Errorf("--backup-pvc= bundle must not contain %q", absent)
+		}
+	}
+}
+
 // TestManifestsRendersReaper proves the happy path with the full retention trio:
 // a batch/v1 CronJob is emitted, named felis-reaper, mounting the backup PVC at the
 // supplied archive path.
@@ -150,7 +175,7 @@ func TestManifestsRendersReaper(t *testing.T) {
 	// this generator cannot verify (else a misarranged hostPath silently no-ops
 	// retention): the <path>/<pvc> arrangement-dependency and the multi-node
 	// nodeSelector hazard.
-	for _, want := range []string{"local-path-provisioner", "nodeSelector"} {
+	for _, want := range []string{"local-path", "nodeSelector"} {
 		if !strings.Contains(errBuf.String(), want) {
 			t.Errorf("reaper render must warn operators about %q on stderr, got %q", want, errBuf.String())
 		}