fix: track and report file restore failures

Restore previously logged errors for individual files but returned
success even if files failed. Now tracks failed files in RestoreResult,
reports them in the summary output, and returns an error if any files
failed to restore.

Fixes #21

internal/vaultik/restore.go

@@ -118,6 +118,8 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 
 		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)
+			result.FilesFailed++
+			result.FailedFiles = append(result.FailedFiles, file.Path.String())
 			// Continue with other files
 			continue
 		}
@@ -147,6 +149,13 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 		result.Duration.Round(time.Second),
 	)
 
+	if result.FilesFailed > 0 {
+		_, _ = fmt.Fprintf(v.Stdout, "\nWARNING: %d file(s) failed to restore:\n", result.FilesFailed)
+		for _, path := range result.FailedFiles {
+			_, _ = fmt.Fprintf(v.Stdout, "  - %s\n", path)
+		}
+	}
+
 	// Run verification if requested
 	if opts.Verify {
 		if err := v.verifyRestoredFiles(v.ctx, repos, files, opts.TargetDir, result); err != nil {
@@ -167,6 +176,10 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 		)
 	}
 
+	if result.FilesFailed > 0 {
+		return fmt.Errorf("%d file(s) failed to restore", result.FilesFailed)
+	}
+
 	return nil
 }