Switch from relative paths to bare names in pointer files

- currentvault now contains just the vault name (e.g., "default")
- current-unlocker now contains just the unlocker name (e.g., "passphrase")
- current version file now contains just the version (e.g., "20231215.001")
- Resolution functions prepend the appropriate directory prefix

internal/vault/integration_test.go

@@ -45,16 +45,16 @@ func TestVaultWithRealFilesystem(t *testing.T) {
 			t.Fatalf("Failed to get vault directory: %v", err)
 		}
 
-		// Verify the currentvault file exists and contains the right relative path
+		// Verify the currentvault file exists and contains just the vault name
 		currentVaultPath := filepath.Join(stateDir, "currentvault")
 		currentVaultContents, err := os.ReadFile(currentVaultPath)
 		if err != nil {
 			t.Fatalf("Failed to read currentvault file: %v", err)
 		}
 
-		expectedRelativePath := "vaults.d/test-vault"
-		if string(currentVaultContents) != expectedRelativePath {
-			t.Errorf("Expected currentvault to contain %q, got %q", expectedRelativePath, string(currentVaultContents))
+		expectedVaultName := "test-vault"
+		if string(currentVaultContents) != expectedVaultName {
+			t.Errorf("Expected currentvault to contain %q, got %q", expectedVaultName, string(currentVaultContents))
 		}
 
 		// Test that ResolveVaultSymlink correctly resolves the path