feat: publish workspace trash lifecycle

internal/core/workspace/manager.go

@@ -490,14 +490,22 @@ func writeWorkspaceIdentity(workspacePath string) (string, error) {
 }
 
 func ensureWorkspaceIdentity(workspacePath string) (string, error) {
-	markerPath := filepath.Join(workspacePath, filepath.FromSlash(workspaceIdentityRelativePath))
-	data, err := os.ReadFile(markerPath)
+	workspaceID, err := readWorkspaceIdentity(workspacePath)
 	if os.IsNotExist(err) {
 		return writeWorkspaceIdentity(workspacePath)
 	}
 	if err != nil {
 		return "", err
 	}
+	return workspaceID, nil
+}
+
+func readWorkspaceIdentity(workspacePath string) (string, error) {
+	markerPath := filepath.Join(workspacePath, filepath.FromSlash(workspaceIdentityRelativePath))
+	data, err := os.ReadFile(markerPath)
+	if err != nil {
+		return "", err
+	}
 	var marker workspaceIdentityMarker
 	if err := json.Unmarshal(data, &marker); err != nil {
 		return "", err
@@ -508,6 +516,33 @@ func ensureWorkspaceIdentity(workspacePath string) (string, error) {
 	return marker.WorkspaceID, nil
 }
 
+// GetWorkspaceTrashIdentity reads a trashed workspace identity without restoring it.
+func (m *Manager) GetWorkspaceTrashIdentity(trashID string) (WorkspaceIdentity, error) {
+	trashID = strings.TrimSpace(trashID)
+	if err := validateWorkspaceTrashID(trashID); err != nil {
+		return WorkspaceIdentity{}, err
+	}
+	trashDir := filepath.Join(m.vaultDir, ".verstak", "trash", "workspaces", trashID)
+	data, err := os.ReadFile(filepath.Join(trashDir, "metadata.json"))
+	if err != nil {
+		return WorkspaceIdentity{}, err
+	}
+	var trashMeta struct {
+		OriginalPath string `json:"originalPath"`
+	}
+	if err := json.Unmarshal(data, &trashMeta); err != nil {
+		return WorkspaceIdentity{}, err
+	}
+	if err := validateWorkspaceName(trashMeta.OriginalPath); err != nil {
+		return WorkspaceIdentity{}, err
+	}
+	workspaceID, err := readWorkspaceIdentity(filepath.Join(trashDir, trashMeta.OriginalPath))
+	if err != nil {
+		return WorkspaceIdentity{}, err
+	}
+	return WorkspaceIdentity{WorkspaceID: workspaceID, RootPath: trashMeta.OriginalPath, State: "trashed"}, nil
+}
+
 // ListWorkspaceTemplates returns selectable built-ins in their presentation order.
 func (m *Manager) ListWorkspaceTemplates() []WorkspaceTemplate {
 	templates := make([]WorkspaceTemplate, 0, len(builtInTemplates))
@@ -647,6 +682,83 @@ func (m *Manager) TrashWorkspace(name string) (TrashResult, error) {
 	return result, nil
 }
 
+// RestoreWorkspaceTrash restores a trashed workspace under targetName without changing its identity.
+func (m *Manager) RestoreWorkspaceTrash(trashID, targetName string) (Workspace, error) {
+	trashID = strings.TrimSpace(trashID)
+	targetName = strings.TrimSpace(targetName)
+	if err := validateWorkspaceTrashID(trashID); err != nil {
+		return Workspace{}, err
+	}
+	if err := validateWorkspaceName(targetName); err != nil {
+		return Workspace{}, err
+	}
+	trashDir := filepath.Join(m.vaultDir, ".verstak", "trash", "workspaces", trashID)
+	data, err := os.ReadFile(filepath.Join(trashDir, "metadata.json"))
+	if err != nil {
+		return Workspace{}, err
+	}
+	var trashMeta struct {
+		OriginalPath string `json:"originalPath"`
+	}
+	if err := json.Unmarshal(data, &trashMeta); err != nil {
+		return Workspace{}, err
+	}
+	if err := validateWorkspaceName(trashMeta.OriginalPath); err != nil {
+		return Workspace{}, err
+	}
+	payloadPath := filepath.Join(trashDir, trashMeta.OriginalPath)
+	if err := ensureExistingWorkspaceDir(payloadPath, trashMeta.OriginalPath); err != nil {
+		return Workspace{}, err
+	}
+	targetPath := filepath.Join(m.vaultDir, targetName)
+	if _, err := os.Lstat(targetPath); err == nil {
+		return Workspace{}, fmt.Errorf("conflict: %s", targetName)
+	} else if !os.IsNotExist(err) {
+		return Workspace{}, err
+	}
+	if err := os.Rename(payloadPath, targetPath); err != nil {
+		return Workspace{}, err
+	}
+	restored := true
+	defer func() {
+		if restored {
+			_ = os.Rename(targetPath, payloadPath)
+		}
+	}()
+	if err := moveIfExists(filepath.Join(trashDir, "workspace.metadata.json"), m.metadataPath(targetName)); err != nil {
+		return Workspace{}, err
+	}
+	workspaceID, err := ensureWorkspaceIdentity(targetPath)
+	if err != nil {
+		return Workspace{}, err
+	}
+	if err := os.RemoveAll(trashDir); err != nil {
+		return Workspace{}, err
+	}
+	restored = false
+	return Workspace{ID: workspaceID, Name: targetName, RootPath: targetName}, nil
+}
+
+func validateWorkspaceTrashID(trashID string) error {
+	if trashID == "" || strings.ContainsAny(trashID, `/\\`) || filepath.Clean(trashID) != trashID {
+		return fmt.Errorf("invalid workspace trash ID")
+	}
+	return nil
+}
+
+// PurgeWorkspaceTrash permanently removes a workspace trash entry.
+func (m *Manager) PurgeWorkspaceTrash(trashID string) error {
+	trashID = strings.TrimSpace(trashID)
+	if err := validateWorkspaceTrashID(trashID); err != nil {
+		return err
+	}
+	trashDir := filepath.Join(m.vaultDir, ".verstak", "trash", "workspaces", trashID)
+	if _, err := os.Stat(filepath.Join(trashDir, "metadata.json")); err != nil {
+		return err
+	}
+	return os.RemoveAll(trashDir)
+}
+
 // GetWorkspaceMetadata returns stored metadata or safe generic metadata.
 func (m *Manager) GetWorkspaceMetadata(name string) (Metadata, error) {
 	name = strings.TrimSpace(name)

internal/core/workspace/manager_test.go

@@ -412,6 +412,47 @@ func TestRepairWorkspaceIdentityRegeneratesCopiedMarker(t *testing.T) {
 	}
 }
 
+func TestRestoreWorkspaceTrashPreservesIdentity(t *testing.T) {
+	vaultDir := newVaultDir(t)
+	m := NewManager(vaultDir)
+	created, err := m.CreateWorkspace("Client", "default")
+	if err != nil {
+		t.Fatalf("CreateWorkspace: %v", err)
+	}
+	trashed, err := m.TrashWorkspace("Client")
+	if err != nil {
+		t.Fatalf("TrashWorkspace: %v", err)
+	}
+	restored, err := m.RestoreWorkspaceTrash(trashed.TrashID, "Client-Restored")
+	if err != nil {
+		t.Fatalf("RestoreWorkspaceTrash: %v", err)
+	}
+	if restored.Name != "Client-Restored" || restored.ID != created.ID {
+		t.Fatalf("restored = %+v, want name Client-Restored and ID %q", restored, created.ID)
+	}
+	if _, err := os.Stat(filepath.Join(vaultDir, "Client-Restored", ".verstak", "workspace.json")); err != nil {
+		t.Fatalf("restored marker: %v", err)
+	}
+}
+
+func TestPurgeWorkspaceTrashRemovesPayload(t *testing.T) {
+	vaultDir := newVaultDir(t)
+	m := NewManager(vaultDir)
+	if _, err := m.CreateWorkspace("Client", "default"); err != nil {
+		t.Fatalf("CreateWorkspace: %v", err)
+	}
+	trashed, err := m.TrashWorkspace("Client")
+	if err != nil {
+		t.Fatalf("TrashWorkspace: %v", err)
+	}
+	if err := m.PurgeWorkspaceTrash(trashed.TrashID); err != nil {
+		t.Fatalf("PurgeWorkspaceTrash: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(vaultDir, ".verstak", "trash", "workspaces", trashed.TrashID)); !os.IsNotExist(err) {
+		t.Fatalf("workspace trash remains, stat err=%v", err)
+	}
+}
+
 func TestCreateAndRenameConflictsAreExplicit(t *testing.T) {
 	vaultDir := newVaultDir(t)
 	mustMkdir(t, filepath.Join(vaultDir, "Existing"))