feat(shell): add parallel bash shell subsystem auto-started per workspace

Co-Authored-By: Claude <noreply@anthropic.com>

internal/service/workspace_service.go

@@ -4,6 +4,7 @@ import (
 	"log/slog"
 
 	"codespace/internal/process"
+	"codespace/internal/shell"
 	"codespace/internal/workspace"
 )
 
@@ -11,16 +12,17 @@ import (
 type WorkspaceService struct {
 	workspaces workspace.Manager
 	processes  process.Manager
+	shells     shell.Manager
 	logger     *slog.Logger
 }
 
 // NewWorkspaceService creates a WorkspaceService.
 // If lg is nil, slog.Default() is used.
-func NewWorkspaceService(workspaces workspace.Manager, processes process.Manager, lg *slog.Logger) *WorkspaceService {
+func NewWorkspaceService(workspaces workspace.Manager, processes process.Manager, shells shell.Manager, lg *slog.Logger) *WorkspaceService {
 	if lg == nil {
 		lg = slog.Default()
 	}
-	return &WorkspaceService{workspaces: workspaces, processes: processes, logger: lg}
+	return &WorkspaceService{workspaces: workspaces, processes: processes, shells: shells, logger: lg}
 }
 
 // Create creates a new workspace.
@@ -30,6 +32,11 @@ func (s *WorkspaceService) Create(id string) (*workspace.Workspace, error) {
 		return nil, err
 	}
 	s.logger.Info("workspace created", "workspace_id", id)
+
+	if err := s.shells.Start(ws.ID, ws.Root); err != nil {
+		s.logger.Warn("failed to auto-start shell for workspace", "workspace_id", id, "error", err)
+	}
+
 	return ws, nil
 }
 
@@ -45,6 +52,10 @@ func (s *WorkspaceService) List() ([]workspace.Workspace, error) {
 
 // Delete stops any running process for the workspace, then removes it.
 func (s *WorkspaceService) Delete(id string) error {
+	if err := s.shells.Stop(id); err != nil {
+		s.logger.Warn("failed to stop workspace shell before delete", "workspace_id", id, "error", err)
+	}
+
 	status := s.processes.Status(id)
 	if status.Running {
 		if err := s.processes.Stop(id); err != nil {