Give every new unlocker a directory of its own (closes #71)

A passphrase unlocker added to a vault that had one, and a PGP, keychain
or Secure Enclave unlocker added on the same day as another of its type,
were written into the existing unlocker's directory file by file, so a
crash part-way left a current unlocker whose files did not belong
together.

Unlocker directories, keychain items and Secure Enclave keys are now
named with the time to the nanosecond, and secret.WriteDir refuses a
directory that exists. Adding a passphrase unlocker writes the new one,
points current-unlocker at it, and only then removes the vault's other
passphrase unlockers.

Model: opus-5-5

internal/cli/integration_test.go

@@ -366,8 +366,15 @@ func test01Initialize(t *testing.T, tempDir, testMnemonic, testPassphrase string
 	unlockersDir := filepath.Join(defaultVaultDir, "unlockers.d")
 	verifyFileExists(t, unlockersDir)
 
+	// Check current-unlocker file names the unlocker's directory
+	currentUnlockerFile := filepath.Join(defaultVaultDir, "current-unlocker")
+	verifyFileExists(t, currentUnlockerFile)
+
+	currentUnlockerContent := readFile(t, currentUnlockerFile)
+	assert.Contains(t, string(currentUnlockerContent), "passphrase", "current unlocker should point to passphrase type")
+
 	// Verify passphrase unlocker was created
-	passphraseUnlockerDir := filepath.Join(unlockersDir, "passphrase")
+	passphraseUnlockerDir := filepath.Join(unlockersDir, string(currentUnlockerContent))
 	verifyFileExists(t, passphraseUnlockerDir)
 
 	// Check unlocker metadata
@@ -382,13 +389,6 @@ func test01Initialize(t *testing.T, tempDir, testMnemonic, testPassphrase string
 	encryptedLTPubKey := filepath.Join(passphraseUnlockerDir, "pub.age")
 	verifyFileExists(t, encryptedLTPubKey)
 
-	// Check current-unlocker file contains the relative path
-	currentUnlockerFile := filepath.Join(defaultVaultDir, "current-unlocker")
-	verifyFileExists(t, currentUnlockerFile)
-
-	currentUnlockerContent := readFile(t, currentUnlockerFile)
-	assert.Contains(t, string(currentUnlockerContent), "passphrase", "current unlocker should point to passphrase type")
-
 	// Verify vault-metadata.json in vault
 	vaultMetadata := filepath.Join(defaultVaultDir, "vault-metadata.json")
 	verifyFileExists(t, vaultMetadata)
@@ -537,7 +537,8 @@ func test04ImportMnemonic(t *testing.T, tempDir, testMnemonic, testPassphrase st
 	verifyFileExists(t, pubKeyFile)
 
 	// Verify passphrase unlocker was created
-	passphraseUnlockerDir := filepath.Join(workVaultDir, "unlockers.d", "passphrase")
+	currentUnlocker := readFile(t, filepath.Join(workVaultDir, "current-unlocker"))
+	passphraseUnlockerDir := filepath.Join(workVaultDir, "unlockers.d", string(currentUnlocker))
 	verifyFileExists(t, passphraseUnlockerDir)
 
 	// Check unlocker files

internal/cli/path_traversal_test.go

@@ -181,7 +181,7 @@ func TestInvalidSecretNameLeavesVaultsUnchanged(t *testing.T) {
 
 	vaultDir := testStateDir + "/vaults.d/default"
 	require.Contains(t, before, vaultDir+"/secrets.d/x/")
-	require.Contains(t, before, vaultDir+"/unlockers.d/passphrase/")
+	require.Contains(t, before, vaultDir+"/current-unlocker")
 	require.Equal(t, "default", before[testStateDir+"/currentvault"])
 
 	cmd := &cobra.Command{}

internal/cli/unlockers.go

@@ -603,8 +603,8 @@ func (cli *Instance) addPassphraseUnlocker(cmd *cobra.Command) error {
 
 	cmd.Printf("Created passphrase unlocker: %s\n", passphraseUnlocker.GetID())
 
-	// Auto-select the newly created unlocker
-	autoSelectUnlocker(cmd, vlt, passphraseUnlocker.GetID())
+	// CreatePassphraseUnlocker has already made it the current unlocker
+	cmd.Printf("Automatically selected as current unlocker\n")
 
 	return nil
 }