feat(service): expose subscribe, input, exit status for ws handler

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

internal/service/process_service.go

@@ -3,6 +3,8 @@ package service
 import (
 	"log/slog"
 
+	"io"
+
 	"codespace/internal/process"
 	"codespace/internal/workspace"
 )
@@ -70,3 +72,27 @@ func (s *ProcessService) Status(workspaceID string) (process.Status, error) {
 	}
 	return s.processes.Status(workspaceID), nil
 }
+
+// Subscribe subscribes to output events for the workspace process.
+func (s *ProcessService) Subscribe(workspaceID string) (process.Subscription, error) {
+	if _, err := s.workspaces.Get(workspaceID); err != nil {
+		return nil, err
+	}
+	return s.processes.Subscribe(workspaceID)
+}
+
+// Input returns the stdin writer for the workspace process.
+func (s *ProcessService) Input(workspaceID string) (io.WriteCloser, error) {
+	if _, err := s.workspaces.Get(workspaceID); err != nil {
+		return nil, err
+	}
+	return s.processes.Stdin(workspaceID)
+}
+
+// ExitStatus returns the exit status for the workspace process.
+func (s *ProcessService) ExitStatus(workspaceID string) (process.ExitInfo, error) {
+	if _, err := s.workspaces.Get(workspaceID); err != nil {
+		return process.ExitInfo{}, err
+	}
+	return s.processes.ExitStatus(workspaceID)
+}