feat(v0.5): add launch_dir field to TaskMeta

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/workspace/metadata.go

@@ -12,7 +12,9 @@ import (
 
 // TaskMeta represents the task.yaml schema.
 // The Type field is v0.3+; older workspaces without this field are treated as "task"
-// (see EffectiveType). Field order in this struct is the YAML output order.
+// (see EffectiveType). LaunchDir is v0.5+; empty for tasks and pre-v0.5 projects,
+// defaults to the project slug for new projects. Field order in this struct is
+// the YAML output order.
 type TaskMeta struct {
 	ID            string     `yaml:"id"`
 	Slug          string     `yaml:"slug"`
@@ -26,6 +28,7 @@ type TaskMeta struct {
 	Agent         string     `yaml:"agent"`
 	WorkspacePath string     `yaml:"workspace_path"`
 	ArchivedAt    *time.Time `yaml:"archived_at"`
+	LaunchDir     string     `yaml:"launch_dir,omitempty"`
 }
 
 // EffectiveType returns "task" or "project". An empty or missing Type field

internal/workspace/metadata_test.go

@@ -255,3 +255,56 @@ func TestMetaArchive(t *testing.T) {
 		t.Errorf("ArchivedAt: got %v, want %v", got.ArchivedAt, archiveTime)
 	}
 }
+
+func TestMetaLaunchDirRoundTrip(t *testing.T) {
+	tmp := t.TempDir()
+	path := filepath.Join(tmp, "task.yaml")
+
+	meta := &TaskMeta{
+		ID:        "test",
+		Slug:      "demo",
+		Title:     "demo",
+		CreatedAt: time.Now().UTC().Truncate(time.Second),
+		UpdatedAt: time.Now().UTC().Truncate(time.Second),
+		Status:    "active",
+		Category:  "projects",
+		Type:      "project",
+		Mode:      "local",
+		Agent:     "claude",
+		LaunchDir: "demo",
+	}
+	if err := WriteMeta(path, meta); err != nil {
+		t.Fatalf("WriteMeta: %v", err)
+	}
+	got, err := ReadMeta(path)
+	if err != nil {
+		t.Fatalf("ReadMeta: %v", err)
+	}
+	if got.LaunchDir != "demo" {
+		t.Errorf("LaunchDir round-trip: got %q, want %q", got.LaunchDir, "demo")
+	}
+}
+
+func TestMetaLaunchDirOmittedWhenEmpty(t *testing.T) {
+	// Backward compat: a task workspace with no LaunchDir must not serialize
+	// a launch_dir key (keeps on-disk task.yaml clean for pre-v0.5 shape).
+	tmp := t.TempDir()
+	path := filepath.Join(tmp, "task.yaml")
+	meta := &TaskMeta{
+		ID: "t", Slug: "t", Title: "t",
+		CreatedAt: time.Now().UTC().Truncate(time.Second),
+		UpdatedAt: time.Now().UTC().Truncate(time.Second),
+		Status: "active", Category: "general", Type: "task",
+		Mode: "local", Agent: "claude",
+	}
+	if err := WriteMeta(path, meta); err != nil {
+		t.Fatalf("WriteMeta: %v", err)
+	}
+	body, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile: %v", err)
+	}
+	if strings.Contains(string(body), "launch_dir") {
+		t.Errorf("empty LaunchDir must not serialize launch_dir key; got:\n%s", body)
+	}
+}