Change FileProgress callback to channel-based progress

Replace callback-based progress reporting in Builder.AddFile with
channel-based FileHashProgress for consistency with EnumerateStatus
and ScanStatus patterns. Update scanner.go to use the new channel API.

internal/cli/check.go

@@ -2,20 +2,58 @@ package cli
 
 import (
 	"fmt"
+	"path/filepath"
 	"time"
 
+	"github.com/spf13/afero"
 	"github.com/urfave/cli/v2"
 	"sneak.berlin/go/mfer/internal/checker"
 	"sneak.berlin/go/mfer/internal/log"
 )
 
+// findManifest looks for a manifest file in the given directory.
+// It checks for index.mf and .index.mf, returning the first one found.
+func findManifest(fs afero.Fs, dir string) (string, error) {
+	candidates := []string{"index.mf", ".index.mf"}
+	for _, name := range candidates {
+		path := filepath.Join(dir, name)
+		exists, err := afero.Exists(fs, path)
+		if err != nil {
+			return "", err
+		}
+		if exists {
+			return path, nil
+		}
+	}
+	return "", fmt.Errorf("no manifest found in %s (looked for index.mf and .index.mf)", dir)
+}
+
 func (mfa *CLIApp) checkManifestOperation(ctx *cli.Context) error {
 	log.Debug("checkManifestOperation()")
 
-	// Get manifest path from args, default to index.mf
-	manifestPath := "index.mf"
+	var manifestPath string
+	var err error
+
 	if ctx.Args().Len() > 0 {
-		manifestPath = ctx.Args().Get(0)
+		arg := ctx.Args().Get(0)
+		// Check if arg is a directory or a file
+		info, statErr := mfa.Fs.Stat(arg)
+		if statErr == nil && info.IsDir() {
+			// It's a directory, look for manifest inside
+			manifestPath, err = findManifest(mfa.Fs, arg)
+			if err != nil {
+				return err
+			}
+		} else {
+			// Treat as a file path
+			manifestPath = arg
+		}
+	} else {
+		// No argument, look in current directory
+		manifestPath, err = findManifest(mfa.Fs, ".")
+		if err != nil {
+			return err
+		}
 	}
 
 	basePath := ctx.String("base")
@@ -40,10 +78,20 @@ func (mfa *CLIApp) checkManifestOperation(ctx *cli.Context) error {
 		progress = make(chan checker.CheckStatus, 1)
 		go func() {
 			for status := range progress {
-				log.Progressf("Checking: %d/%d files, %d failures",
-					status.CheckedFiles,
-					status.TotalFiles,
-					status.Failures)
+				if status.ETA > 0 {
+					log.Progressf("Checking: %d/%d files, %.1f MB/s, ETA %s, %d failures",
+						status.CheckedFiles,
+						status.TotalFiles,
+						status.BytesPerSec/1e6,
+						status.ETA.Round(time.Second),
+						status.Failures)
+				} else {
+					log.Progressf("Checking: %d/%d files, %.1f MB/s, %d failures",
+						status.CheckedFiles,
+						status.TotalFiles,
+						status.BytesPerSec/1e6,
+						status.Failures)
+				}
 			}
 			log.ProgressDone()
 		}()