refactor: unify agent startup with Manager pattern

- Create mayor.Manager for mayor lifecycle (Start/Stop/IsRunning/Status)
- Create deacon.Manager for deacon lifecycle with respawn loop
- Move session.Manager to polecat.SessionManager (clearer naming)
- Add zombie session detection for mayor/deacon (kills tmux if Claude dead)
- Remove duplicate session startup code from up.go, start.go, mayor.go
- Rename sessMgr -> polecatMgr for consistency
- Make witness/refinery SessionName() public for status display

All agent types now follow the same Manager pattern:
  mgr := agent.NewManager(...)
  mgr.Start(...)
  mgr.Stop()
  mgr.IsRunning()
  mgr.Status()

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/polecat/session_manager_test.go

@@ -0,0 +1,192 @@
+package polecat
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/steveyegge/gastown/internal/rig"
+	"github.com/steveyegge/gastown/internal/tmux"
+)
+
+func TestSessionName(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "gastown",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	name := m.SessionName("Toast")
+	if name != "gt-gastown-Toast" {
+		t.Errorf("sessionName = %q, want gt-gastown-Toast", name)
+	}
+}
+
+func TestSessionManagerPolecatDir(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "gastown",
+		Path:     "/home/user/ai/gastown",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	dir := m.polecatDir("Toast")
+	expected := "/home/user/ai/gastown/polecats/Toast"
+	if dir != expected {
+		t.Errorf("polecatDir = %q, want %q", dir, expected)
+	}
+}
+
+func TestHasPolecat(t *testing.T) {
+	root := t.TempDir()
+	// hasPolecat checks filesystem, so create actual directories
+	for _, name := range []string{"Toast", "Cheedo"} {
+		if err := os.MkdirAll(filepath.Join(root, "polecats", name), 0755); err != nil {
+			t.Fatalf("mkdir: %v", err)
+		}
+	}
+
+	r := &rig.Rig{
+		Name:     "gastown",
+		Path:     root,
+		Polecats: []string{"Toast", "Cheedo"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	if !m.hasPolecat("Toast") {
+		t.Error("expected hasPolecat(Toast) = true")
+	}
+	if !m.hasPolecat("Cheedo") {
+		t.Error("expected hasPolecat(Cheedo) = true")
+	}
+	if m.hasPolecat("Unknown") {
+		t.Error("expected hasPolecat(Unknown) = false")
+	}
+}
+
+func TestStartPolecatNotFound(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "gastown",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	err := m.Start("Unknown", SessionStartOptions{})
+	if err == nil {
+		t.Error("expected error for unknown polecat")
+	}
+}
+
+func TestIsRunningNoSession(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "gastown",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	running, err := m.IsRunning("Toast")
+	if err != nil {
+		t.Fatalf("IsRunning: %v", err)
+	}
+	if running {
+		t.Error("expected IsRunning = false for non-existent session")
+	}
+}
+
+func TestSessionManagerListEmpty(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "test-rig-unlikely-name",
+		Polecats: []string{},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	infos, err := m.List()
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	if len(infos) != 0 {
+		t.Errorf("infos count = %d, want 0", len(infos))
+	}
+}
+
+func TestStopNotFound(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "test-rig",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	err := m.Stop("Toast", false)
+	if err != ErrSessionNotFound {
+		t.Errorf("Stop = %v, want ErrSessionNotFound", err)
+	}
+}
+
+func TestCaptureNotFound(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "test-rig",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	_, err := m.Capture("Toast", 50)
+	if err != ErrSessionNotFound {
+		t.Errorf("Capture = %v, want ErrSessionNotFound", err)
+	}
+}
+
+func TestInjectNotFound(t *testing.T) {
+	r := &rig.Rig{
+		Name:     "test-rig",
+		Polecats: []string{"Toast"},
+	}
+	m := NewSessionManager(tmux.NewTmux(), r)
+
+	err := m.Inject("Toast", "hello")
+	if err != ErrSessionNotFound {
+		t.Errorf("Inject = %v, want ErrSessionNotFound", err)
+	}
+}
+
+// TestPolecatCommandFormat verifies the polecat session command exports
+// GT_ROLE, GT_RIG, GT_POLECAT, and BD_ACTOR inline before starting Claude.
+// This is a regression test for gt-y41ep - env vars must be exported inline
+// because tmux SetEnvironment only affects new panes, not the current shell.
+func TestPolecatCommandFormat(t *testing.T) {
+	// This test verifies the expected command format.
+	// The actual command is built in Start() but we test the format here
+	// to document and verify the expected behavior.
+
+	rigName := "gastown"
+	polecatName := "Toast"
+	expectedBdActor := "gastown/polecats/Toast"
+
+	// Build the expected command format (mirrors Start() logic)
+	expectedPrefix := "export GT_ROLE=polecat GT_RIG=" + rigName + " GT_POLECAT=" + polecatName + " BD_ACTOR=" + expectedBdActor + " GIT_AUTHOR_NAME=" + expectedBdActor
+	expectedSuffix := "&& claude --dangerously-skip-permissions"
+
+	// The command must contain all required env exports
+	requiredParts := []string{
+		"export",
+		"GT_ROLE=polecat",
+		"GT_RIG=" + rigName,
+		"GT_POLECAT=" + polecatName,
+		"BD_ACTOR=" + expectedBdActor,
+		"GIT_AUTHOR_NAME=" + expectedBdActor,
+		"claude --dangerously-skip-permissions",
+	}
+
+	// Verify expected format contains all required parts
+	fullCommand := expectedPrefix + " " + expectedSuffix
+	for _, part := range requiredParts {
+		if !strings.Contains(fullCommand, part) {
+			t.Errorf("Polecat command should contain %q", part)
+		}
+	}
+
+	// Verify GT_ROLE is specifically "polecat" (not "mayor" or "crew")
+	if !strings.Contains(fullCommand, "GT_ROLE=polecat") {
+		t.Error("GT_ROLE must be 'polecat', not 'mayor' or 'crew'")
+	}
+}