Replace restore progress bars with periodic ui.Progress lines

Restore and verify no longer use schollz/progressbar. Instead they emit
a periodic status line every 15 s via ui.Writer.Progress, matching the
cadence and shape of the snapshot create scanner output. The lines
include files done, byte counts, throughput in bits/sec, elapsed,
absolute ETA, and remaining duration — same conventions as snapshot
create. The progressbar dependency, the newProgressBar/isTerminal
helpers, and the unused printfStderr helper are removed; go.mod loses
schollz/progressbar plus its colorstring and uniseg transitive deps.

Adds --debug timing instrumentation throughout the restore hot path so
the next slow-restore report can pinpoint which stage is the
bottleneck. Per-file: file-chunks query, output Create, per-chunk blob
DB lookups, cache get/put, blob download, chunk write, sweeper call.
Per-blob-download: fetch-setup (Get + Stat) vs read+decrypt+decompress
vs close-and-verify. FetchBlob splits the Storage.Get and Storage.Stat
round-trips so an expensive size-stat is visible separately.

internal/vaultik/blob_fetch.go

@@ -6,9 +6,11 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io"
+	"time"
 
 	"filippo.io/age"
 	"sneak.berlin/go/vaultik/internal/blobgen"
+	"sneak.berlin/go/vaultik/internal/log"
 )
 
 // hashVerifyReader wraps a blobgen.Reader and verifies the double-SHA-256 hash
@@ -75,19 +77,34 @@ func (v *Vaultik) FetchAndDecryptBlob(ctx context.Context, blobHash string, expe
 }
 
 // FetchBlob downloads a blob and returns a reader for the encrypted data.
+// Times the Storage.Get and Storage.Stat round-trips separately at
+// debug level so we can see whether the size-only Stat (which is an
+// extra request on every fetch) is hurting throughput.
 func (v *Vaultik) FetchBlob(ctx context.Context, blobHash string, expectedSize int64) (io.ReadCloser, int64, error) {
 	blobPath := fmt.Sprintf("blobs/%s/%s/%s", blobHash[:2], blobHash[2:4], blobHash)
 
+	t0 := time.Now()
 	rc, err := v.Storage.Get(ctx, blobPath)
+	getDur := time.Since(t0)
 	if err != nil {
 		return nil, 0, fmt.Errorf("downloading blob %s: %w", blobHash[:16], err)
 	}
 
+	t0 = time.Now()
 	info, err := v.Storage.Stat(ctx, blobPath)
+	statDur := time.Since(t0)
 	if err != nil {
 		_ = rc.Close()
 		return nil, 0, fmt.Errorf("stat blob %s: %w", blobHash[:16], err)
 	}
 
+	log.Debug("FetchBlob round-trips",
+		"hash", blobHash[:16],
+		"ms_storage_get", getDur.Milliseconds(),
+		"ms_storage_stat", statDur.Milliseconds(),
+		"expected_size", expectedSize,
+		"stat_size", info.Size,
+	)
+
 	return rc, info.Size, nil
 }