Drop mimeType and ctime from the manifest format (closes #235)

Nothing goes in the 1.0 manifest that 1.0 does not read or write, and
mfer never wrote either field. mf.proto now reserves the numbers 301 and
303 and both names in MFFilePath, and mf.pb.go is regenerated. The
decoded-size check counts only file entries, hashes and timestamps,
export prints no ctime, and FileEntry loses the Ctime nothing set.
FORMAT.md and the README no longer describe either field.

The test of entries that decode too large gives each entry a second,
empty hash: an entry with one hash and a modification time can no
longer reach 8 times its size.

Model: opus-5-5

internal/cli/export.go

@@ -17,7 +17,6 @@ type ExportEntry struct {
 	Size   int64    `json:"size"`
 	Hashes []string `json:"hashes"`
 	Mtime  *string  `json:"mtime,omitempty"`
-	Ctime  *string  `json:"ctime,omitempty"`
 	Mode   string   `json:"mode"` // octal, "0000" when none was recorded
 }
 
@@ -61,12 +60,6 @@ func (mfa *CLIApp) exportManifestOperation(
 			entry.Mtime = &t
 		}
 
-		if f.GetCtime() != nil {
-			t := time.Unix(f.GetCtime().GetSeconds(), int64(f.GetCtime().GetNanos())).
-				UTC().Format(time.RFC3339Nano)
-			entry.Ctime = &t
-		}
-
 		entries = append(entries, entry)
 	}
 

internal/cli/export_test.go

@@ -4,8 +4,10 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"maps"
 	"net/http"
 	"net/http/httptest"
+	"slices"
 	"testing"
 
 	"github.com/spf13/afero"
@@ -84,6 +86,36 @@ func TestExportManifestOperation(t *testing.T) {
 	assert.True(t, pathSet["sub/file.txt"])
 }
 
+// export prints the fields of a file entry and nothing else, so no ctime.
+func TestExportPrintsOnlyFileEntryFields(t *testing.T) {
+	t.Parallel()
+
+	manifestData := buildTestManifest(t, map[string][]byte{"entry.txt": []byte("aaa")})
+
+	fs := afero.NewMemMapFs()
+	require.NoError(t, afero.WriteFile(fs, "/test.mf", manifestData, 0o644))
+
+	var stdout, stderr bytes.Buffer
+
+	exitCode := runCLI(&RunOptions{
+		Appname: testApp,
+		Args:    []string{testApp, testCmdExport, "/test.mf"},
+		Stdin:   &bytes.Buffer{},
+		Stdout:  &stdout,
+		Stderr:  &stderr,
+		Fs:      fs,
+	})
+
+	require.Equal(t, 0, exitCode, "stderr: %s", stderr.String())
+
+	var entries []map[string]json.RawMessage
+	require.NoError(t, json.Unmarshal(stdout.Bytes(), &entries))
+	require.Len(t, entries, 1)
+	assert.Equal(t,
+		[]string{"hashes", "mode", "mtime", "path", "size"},
+		slices.Sorted(maps.Keys(entries[0])))
+}
+
 func TestExportFromHTTPURL(t *testing.T) {
 	t.Parallel()