Replace symlinks with plain files containing relative paths

- Remove all symlink creation and resolution in favor of plain files
- currentvault file now contains relative path like "vaults.d/default"
- current-unlocker file now contains relative path like "unlockers.d/passphrase"
- current version file now contains relative path like "versions/20231215.001"
- Simplify path resolution to just read file contents and join with parent dir
- Update all tests to read files instead of using os.Readlink

internal/vault/integration_test.go

@@ -26,9 +26,9 @@ func TestVaultWithRealFilesystem(t *testing.T) {
 	t.Setenv(secret.EnvMnemonic, testMnemonic)
 	t.Setenv(secret.EnvUnlockPassphrase, "test-passphrase")
 
-	// Test symlink handling
-	t.Run("SymlinkHandling", func(t *testing.T) {
-		stateDir := filepath.Join(tempDir, "symlink-test")
+	// Test currentvault file handling (plain file with relative path)
+	t.Run("CurrentVaultFileHandling", func(t *testing.T) {
+		stateDir := filepath.Join(tempDir, "currentvault-test")
 		if err := os.MkdirAll(stateDir, 0o700); err != nil {
 			t.Fatalf("Failed to create state dir: %v", err)
 		}
@@ -45,31 +45,26 @@ func TestVaultWithRealFilesystem(t *testing.T) {
 			t.Fatalf("Failed to get vault directory: %v", err)
 		}
 
-		// Create a symlink to the vault directory in a different location
-		symlinkPath := filepath.Join(tempDir, "test-symlink")
-		if err := os.Symlink(vaultDir, symlinkPath); err != nil {
-			t.Fatalf("Failed to create symlink: %v", err)
+		// Verify the currentvault file exists and contains the right relative path
+		currentVaultPath := filepath.Join(stateDir, "currentvault")
+		currentVaultContents, err := os.ReadFile(currentVaultPath)
+		if err != nil {
+			t.Fatalf("Failed to read currentvault file: %v", err)
 		}
 
-		// Test that we can resolve the symlink correctly
-		resolvedPath, err := vault.ResolveVaultSymlink(fs, symlinkPath)
-		if err != nil {
-			t.Fatalf("Failed to resolve symlink: %v", err)
+		expectedRelativePath := "vaults.d/test-vault"
+		if string(currentVaultContents) != expectedRelativePath {
+			t.Errorf("Expected currentvault to contain %q, got %q", expectedRelativePath, string(currentVaultContents))
 		}
 
-		// On some platforms, the resolved path might have different case or format
-		// We'll use filepath.EvalSymlinks to get the canonical path for comparison
-		expectedPath, err := filepath.EvalSymlinks(vaultDir)
+		// Test that ResolveVaultSymlink correctly resolves the path
+		resolvedPath, err := vault.ResolveVaultSymlink(fs, currentVaultPath)
 		if err != nil {
-			t.Fatalf("Failed to evaluate symlink: %v", err)
-		}
-		actualPath, err := filepath.EvalSymlinks(resolvedPath)
-		if err != nil {
-			t.Fatalf("Failed to evaluate resolved path: %v", err)
+			t.Fatalf("Failed to resolve currentvault path: %v", err)
 		}
 
-		if actualPath != expectedPath {
-			t.Errorf("Expected symlink to resolve to %s, got %s", expectedPath, actualPath)
+		if resolvedPath != vaultDir {
+			t.Errorf("Expected resolved path to be %s, got %s", vaultDir, resolvedPath)
 		}
 	})