fix(host): correct host workspace cleanup on Windows (#883)

## Summary
- Fix host-mode cleanup to remove the job **workspace** directory after a run (instead of leaving checkouts behind).
- On Windows, track step process PIDs and terminate remaining process trees during teardown before attempting workspace deletion (prevents file-lock failures).
- Skip workspace deletion when `bind_workdir` is enabled to avoid conflicting with runner-level task directory cleanup.

## Implementation details
- `HostEnvironment` now records PIDs for started commands and best-effort terminates them on Windows during `Remove()`.
- Workspace removal uses a small retry loop on Windows to handle transient locks.
- `BindWorkdir` is propagated into `HostEnvironment` so cleanup behavior matches runner configuration.

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: silverwind <2021+silverwind@noreply.gitea.com>
Reviewed-on: https://gitea.com/gitea/runner/pulls/883
Reviewed-by: silverwind <2021+silverwind@noreply.gitea.com>

act/container/host_environment_test.go

@@ -13,7 +13,11 @@ import (
 	"path/filepath"
 	"testing"
 
+	"gitea.com/gitea/runner/act/common"
+
+	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // Type assert HostEnvironment implements ExecutionsEnvironment
@@ -69,3 +73,51 @@ func TestGetContainerArchive(t *testing.T) {
 	_, err = reader.Next()
 	assert.ErrorIs(t, err, io.EOF)
 }
+
+func TestHostEnvironmentRemoveCleansWorkdir(t *testing.T) {
+	logger := logrus.New()
+	ctx := common.WithLogger(context.Background(), logrus.NewEntry(logger))
+	base := t.TempDir()
+	miscRoot := filepath.Join(base, "misc")
+	path := filepath.Join(miscRoot, "hostexecutor")
+	require.NoError(t, os.MkdirAll(path, 0o700))
+	workdir := filepath.Join(base, "workspace", "owner", "repo")
+	require.NoError(t, os.MkdirAll(workdir, 0o700))
+
+	e := &HostEnvironment{
+		Path:        path,
+		Workdir:     workdir,
+		BindWorkdir: false,
+		CleanUp: func() {
+			_ = os.RemoveAll(miscRoot)
+		},
+		StdOut: os.Stdout,
+	}
+	require.NoError(t, e.Remove()(ctx))
+	_, err := os.Stat(workdir)
+	assert.ErrorIs(t, err, os.ErrNotExist)
+}
+
+func TestHostEnvironmentRemoveSkipsWorkdirWhenBindWorkdir(t *testing.T) {
+	logger := logrus.New()
+	ctx := common.WithLogger(context.Background(), logrus.NewEntry(logger))
+	base := t.TempDir()
+	miscRoot := filepath.Join(base, "misc")
+	path := filepath.Join(miscRoot, "hostexecutor")
+	require.NoError(t, os.MkdirAll(path, 0o700))
+	workdir := filepath.Join(base, "workspace", "123", "owner", "repo")
+	require.NoError(t, os.MkdirAll(workdir, 0o700))
+
+	e := &HostEnvironment{
+		Path:        path,
+		Workdir:     workdir,
+		BindWorkdir: true,
+		CleanUp: func() {
+			_ = os.RemoveAll(miscRoot)
+		},
+		StdOut: os.Stdout,
+	}
+	require.NoError(t, e.Remove()(ctx))
+	_, err := os.Stat(workdir)
+	require.NoError(t, err)
+}