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/vaultik.go

@@ -147,11 +147,6 @@ func (v *Vaultik) printlnStdout(args ...any) {
 	_, _ = fmt.Fprintln(v.Stdout, args...)
 }
 
-// printfStderr writes formatted output to stderr.
-func (v *Vaultik) printfStderr(format string, args ...any) {
-	_, _ = fmt.Fprintf(v.Stderr, format, args...)
-}
-
 // scanStdin reads a line of input from stdin.
 func (v *Vaultik) scanStdin(a ...any) (int, error) {
 	return fmt.Fscanln(v.Stdin, a...)