Remove internal/macse package and fix all linter issues

- Remove internal/macse package (Secure Enclave experiment)
- Fix errcheck: handle keychain.DeleteItem error return
- Fix lll: break long lines in command descriptions
- Fix mnd: add nolint comment for cobra.ExactArgs(2)
- Fix nlreturn: add blank lines before return/break statements
- Fix revive: add nolint comment for KEYCHAIN_APP_IDENTIFIER constant
- Fix nestif: simplify UnlockersRemove by using new NumSecrets method
- Add NumSecrets() method to vault.Vault for counting secrets
- Update golangci.yml to exclude ALL_CAPS warning (attempted various
  configurations but settled on nolint comment)

All tests pass, code is formatted and linted.

internal/vault/vault.go

@@ -208,3 +208,48 @@ func (v *Vault) GetName() string {
 func (v *Vault) GetFilesystem() afero.Fs {
 	return v.fs
 }
+
+// NumSecrets returns the number of secrets in the vault
+func (v *Vault) NumSecrets() (int, error) {
+	vaultDir, err := v.GetDirectory()
+	if err != nil {
+		return 0, fmt.Errorf("failed to get vault directory: %w", err)
+	}
+
+	secretsDir := filepath.Join(vaultDir, "secrets.d")
+	exists, _ := afero.DirExists(v.fs, secretsDir)
+	if !exists {
+		return 0, nil
+	}
+
+	entries, err := afero.ReadDir(v.fs, secretsDir)
+	if err != nil {
+		return 0, fmt.Errorf("failed to read secrets directory: %w", err)
+	}
+
+	// Count only directories that contain at least one version file
+	count := 0
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		// Check if this secret directory contains any version files
+		secretDir := filepath.Join(secretsDir, entry.Name())
+		versionFiles, err := afero.ReadDir(v.fs, secretDir)
+		if err != nil {
+			continue // Skip directories we can't read
+		}
+
+		// Look for at least one version file (excluding "current" symlink)
+		for _, vFile := range versionFiles {
+			if !vFile.IsDir() && vFile.Name() != "current" {
+				count++
+
+				break // Found at least one version, count this secret
+			}
+		}
+	}
+
+	return count, nil
+}