Keep command output to the README's stdout and stderr rules (closes #224)

The startup banner moves from stdout to stderr, so a `completion`
script, a `config get` value and the hidden `__complete` command print
only their own output. `--quiet`, `--cron` and `--json` still suppress
it.

A failing `remote info`, `prune` or `snapshot remove` under `--json`
now reports its error on stderr. Their reporters returned early under
`--json`, so the failure reached neither stream.

`snapshot verify --quiet` writes no report. A failure is still
returned and printed on stderr, with the same exit status.

Judgement call: the banner's stream, posted on the issue for the owner.

Model: opus-5-5

TODO.md

@@ -31,14 +31,6 @@ the tag exists and is exercised; what is left is merging `next` to
   `snapshot verify --quiet` printed its whole report; it now prints
   none, and a failure still reaches stderr with the same exit status.
 
-- 2026-10-06: Made a backup without `--cron` of a snapshot with two or
-  more `paths` complete instead of panicking with `close of closed
-  channel` ([issue #253](https://git.eeqj.de/sneak/vaultik/issues/253)).
-  `Scan` runs once per path and started and stopped the progress
-  reporter each time, and a second stop panics. The reporter is now
-  started and stopped once per snapshot, around the scans of all its
-  paths.
-
 - 2026-10-06: Made a restore path argument select only that path and
   what is beneath it
   ([issue #223](https://git.eeqj.de/sneak/vaultik/issues/223)). The

internal/snapshot/scanner.go

@@ -224,6 +224,12 @@ func (s *Scanner) Scan(
 		log.Debug("No storage configured, blobs will not be uploaded")
 	}
 
+	// Start progress reporting if enabled
+	if s.progress != nil {
+		s.progress.Start()
+		defer s.progress.Stop()
+	}
+
 	// Phase 0: Repair any state left by an interrupted previous run, then
 	// load known files and chunks from the database into memory for fast
 	// lookup.
@@ -294,9 +300,7 @@ func (s *Scanner) Scan(
 	return result, nil
 }
 
-// GetProgress returns the progress reporter for this scanner, or nil when
-// progress is off. Scan neither starts nor stops it: the caller does,
-// once for all the paths it scans, because a second Stop panics.
+// GetProgress returns the progress reporter for this scanner
 func (s *Scanner) GetProgress() *ProgressReporter {
 	return s.progress
 }

internal/vaultik/snapshot.go

@@ -281,11 +281,6 @@ func (v *Vaultik) resolveSnapshotPaths(snapName string) ([]string, error) {
 func (v *Vaultik) scanAllDirectories(
 	scanner *snapshot.Scanner, resolvedDirs []string, snapshotID string,
 ) (*snapshotStats, error) {
-	if progress := scanner.GetProgress(); progress != nil {
-		progress.Start()
-		defer progress.Stop()
-	}
-
 	stats := &snapshotStats{}
 
 	for i, dir := range resolvedDirs {

internal/vaultik/two_path_snapshot_test.go

@@ -1,71 +0,0 @@
-package vaultik_test
-
-import (
-	"context"
-	"maps"
-	"path/filepath"
-	"testing"
-
-	"github.com/spf13/afero"
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/vaultik/internal/config"
-	"sneak.berlin/go/vaultik/internal/database"
-	"sneak.berlin/go/vaultik/internal/log"
-	"sneak.berlin/go/vaultik/internal/storage"
-	"sneak.berlin/go/vaultik/internal/vaultik"
-)
-
-// A backup without --cron runs the progress reporter while one scanner
-// scans each path of the snapshot in turn. See
-// https://git.eeqj.de/sneak/vaultik/issues/253.
-//
-//nolint:paralleltest // installs the global logger via log.Initialize
-func TestBackupWithoutCronOfTwoPathSnapshotRestoresBothPaths(t *testing.T) {
-	log.Initialize(log.Config{})
-
-	const snapshotName = "data"
-
-	fs := afero.NewOsFs()
-	tempDir := t.TempDir()
-	firstDir := filepath.Join(tempDir, "first")
-	secondDir := filepath.Join(tempDir, "second")
-	storeDir := filepath.Join(tempDir, "remote")
-	restoreDir := filepath.Join(tempDir, "restored")
-	dbPath := filepath.Join(tempDir, "index.sqlite")
-
-	ctx := context.Background()
-	files := writeFaultSourceTree(t, fs, firstDir)
-	maps.Copy(files, writeFaultSourceTree(t, fs, secondDir))
-
-	cfg := faultTestConfig()
-	cfg.IndexPath = dbPath
-	cfg.ChunkSize = config.Size(faultChunkSize)
-	cfg.Snapshots = map[string]config.SnapshotConfig{
-		snapshotName: {Paths: []string{firstDir, secondDir}},
-	}
-
-	store, err := storage.NewFileStorer(storeDir)
-	require.NoError(t, err)
-
-	db, err := database.New(ctx, dbPath)
-	require.NoError(t, err)
-
-	repos := database.NewRepositories(db)
-	v := newBackupVaultik(ctx, cfg, store, repos, db, fs)
-
-	require.NoError(t, v.CreateSnapshot(&vaultik.SnapshotCreateOptions{
-		Snapshots: []string{snapshotName},
-	}))
-
-	id := localSnapshotID(ctx, t, repos, snapshotName)
-	require.NoError(t, db.Close())
-
-	reader := newReaderVaultik(ctx, cfg, store, nil, fs)
-	require.NoError(t, reader.Restore(&vaultik.RestoreOptions{
-		SnapshotID: id,
-		TargetDir:  restoreDir,
-		Verify:     true,
-	}))
-
-	assertRestoredTree(t, fs, restoreDir, files)
-}