secret list gives each secret's own creation and last-update times (closes #142)

secret list and secret list --json gave the time of the listing as every
secret's creation and last-update time, because Secret.LoadMetadata set
both to the current time. It now reads file modification times, so
listing still needs no passphrase: the last update is when the secret's
current file was written, and the creation is when its oldest version's
value.age was written. A move to another vault gives the copied files
the times of the originals.

GetSecretObject no longer loads the times, so secret get keeps its error
for a missing current file; secret list calls LoadMetadata itself.

Judgement call: the creation time comes from value.age, not from the
oldest version's directory, whose time changes when the next add
rewrites that version's metadata.age.

Model: opus-5-5

internal/secret/secret.go

@@ -2,10 +2,11 @@ package secret
 
 import (
 	"errors"
+	"fmt"
 	"log/slog"
+	"os"
 	"path/filepath"
 	"strings"
-	"time"
 
 	"filippo.io/age"
 	"github.com/awnumar/memguard"
@@ -66,31 +67,53 @@ func NewSecret(vault VaultInterface, name string) *Secret {
 		Name:      name,
 		Directory: secretDir,
 		vault:     vault,
-		Metadata: Metadata{
-			CreatedAt: time.Now(),
-			UpdatedAt: time.Now(),
-		},
 	}
 }
 
-// LoadMetadata is deprecated - metadata is now per-version and encrypted
+// LoadMetadata sets the secret's times from the modification times of its
+// files, which can be read without unlocking the vault. UpdatedAt is when
+// the secret's current file was last written, by an add or a promote.
+// CreatedAt is when its oldest version's value.age was written. That file
+// is never rewritten; the version's directory is no use, as its time
+// changes when the next add rewrites the version's metadata.age.
 func (s *Secret) LoadMetadata() error {
-	Debug("LoadMetadata called but is deprecated in versioned model",
-		"secret_name", s.Name)
-	// For backward compatibility, we'll populate with basic info
-	now := time.Now()
+	fs := s.vault.GetFilesystem()
+
+	current, err := fs.Stat(filepath.Join(s.Directory, "current"))
+	if err != nil {
+		return fmt.Errorf("failed to read when secret %s was updated: %w",
+			s.Name, err)
+	}
+
+	versions, err := ListVersions(fs, s.Directory)
+	if err != nil {
+		return err
+	}
+
+	if len(versions) == 0 {
+		return fmt.Errorf("secret %s has no versions: %w", s.Name, os.ErrNotExist)
+	}
+
+	// ListVersions lists the newest version first
+	oldest := versions[len(versions)-1]
+
+	value, err := fs.Stat(
+		filepath.Join(s.Directory, "versions", oldest, "value.age"))
+	if err != nil {
+		return fmt.Errorf("failed to read when secret %s was created: %w",
+			s.Name, err)
+	}
+
 	s.Metadata = Metadata{
-		CreatedAt: now,
-		UpdatedAt: now,
+		CreatedAt: value.ModTime(),
+		UpdatedAt: current.ModTime(),
 	}
 
 	return nil
 }
 
-// GetMetadata returns the secret metadata (deprecated)
+// GetMetadata returns the times LoadMetadata read
 func (s *Secret) GetMetadata() Metadata {
-	Debug("GetMetadata called but is deprecated in versioned model", "secret_name", s.Name)
-
 	return s.Metadata
 }