feat: add progress bar to restore operation

Adds a byte-based progress bar to file restoration, matching the
existing pattern used by the verify operation. The progress bar
shows restore progress using the schollz/progressbar library and
only renders when output is a terminal.

Closes #20

internal/vaultik/restore.go

@@ -111,26 +111,59 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 	result := &RestoreResult{}
 	blobCache := make(map[string][]byte) // Cache downloaded and decrypted blobs
 
-	for i, file := range files {
+	// Calculate total bytes for progress bar
+	var totalBytes int64
+	for _, file := range files {
+		totalBytes += file.Size
+	}
+
+	_, _ = fmt.Fprintf(v.Stdout, "Restoring %d files (%s)...\n",
+		len(files),
+		humanize.Bytes(uint64(totalBytes)),
+	)
+
+	// Create progress bar if output is a terminal
+	var bar *progressbar.ProgressBar
+	if isTerminal() {
+		bar = progressbar.NewOptions64(
+			totalBytes,
+			progressbar.OptionSetDescription("Restoring"),
+			progressbar.OptionSetWriter(os.Stderr),
+			progressbar.OptionShowBytes(true),
+			progressbar.OptionShowCount(),
+			progressbar.OptionSetWidth(40),
+			progressbar.OptionThrottle(100*time.Millisecond),
+			progressbar.OptionOnCompletion(func() {
+				fmt.Fprint(os.Stderr, "\n")
+			}),
+			progressbar.OptionSetRenderBlankState(true),
+		)
+	}
+
+	for _, file := range files {
 		if v.ctx.Err() != nil {
 			return v.ctx.Err()
 		}
 
 		if err := v.restoreFile(v.ctx, repos, file, opts.TargetDir, identity, chunkToBlobMap, blobCache, result); err != nil {
 			log.Error("Failed to restore file", "path", file.Path, "error", err)
-			// Continue with other files
+			// Update progress bar even on failure
+			if bar != nil {
+				_ = bar.Add64(file.Size)
+			}
 			continue
 		}
 
-		// Progress logging
+		// Update progress bar
-		if (i+1)%100 == 0 || i+1 == len(files) {
+		if bar != nil {
-			log.Info("Restore progress",
+			_ = bar.Add64(file.Size)
-				"files", fmt.Sprintf("%d/%d", i+1, len(files)),
-				"bytes", humanize.Bytes(uint64(result.BytesRestored)),
-			)
 		}
 	}
 
+	if bar != nil {
+		_ = bar.Finish()
+	}
+
 	result.Duration = time.Since(startTime)
 
 	log.Info("Restore complete",