feat: add gt up/down commands and daemon doctor check

New commands:
- `gt up` - Idempotent boot command that brings up all services:
  Daemon, Deacon, Mayor, and Witnesses for all rigs
- `gt down` - Graceful shutdown of all services

Doctor improvements:
- New daemon check verifies daemon is running
- Fixable with `gt doctor --fix` to auto-start daemon

The system can run degraded (any services down) but `gt up` ensures
a fully operational Gas Town with one idempotent command.

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

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

internal/cmd/down.go

@@ -0,0 +1,139 @@
+package cmd
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/daemon"
+	"github.com/steveyegge/gastown/internal/style"
+	"github.com/steveyegge/gastown/internal/tmux"
+	"github.com/steveyegge/gastown/internal/workspace"
+)
+
+var downCmd = &cobra.Command{
+	Use:   "down",
+	Short: "Stop all Gas Town services",
+	Long: `Stop all Gas Town long-lived services.
+
+This gracefully shuts down all infrastructure agents:
+
+  • Witnesses - Per-rig polecat managers
+  • Mayor     - Global work coordinator
+  • Deacon    - Health orchestrator
+  • Daemon    - Go background process
+
+Polecats are NOT stopped by this command - use 'gt swarm stop' or
+kill individual polecats with 'gt polecat kill'.
+
+This is useful for:
+  • Taking a break (stop token consumption)
+  • Clean shutdown before system maintenance
+  • Resetting the town to a clean state`,
+	RunE: runDown,
+}
+
+var (
+	downQuiet bool
+	downForce bool
+)
+
+func init() {
+	downCmd.Flags().BoolVarP(&downQuiet, "quiet", "q", false, "Only show errors")
+	downCmd.Flags().BoolVarP(&downForce, "force", "f", false, "Force kill without graceful shutdown")
+	rootCmd.AddCommand(downCmd)
+}
+
+func runDown(cmd *cobra.Command, args []string) error {
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	t := tmux.NewTmux()
+	allOK := true
+
+	// Stop in reverse order of startup
+
+	// 1. Stop witnesses first
+	rigs := discoverRigs(townRoot)
+	for _, rigName := range rigs {
+		sessionName := fmt.Sprintf("gt-%s-witness", rigName)
+		if err := stopSession(t, sessionName); err != nil {
+			printDownStatus(fmt.Sprintf("Witness (%s)", rigName), false, err.Error())
+			allOK = false
+		} else {
+			printDownStatus(fmt.Sprintf("Witness (%s)", rigName), true, "stopped")
+		}
+	}
+
+	// 2. Stop Mayor
+	if err := stopSession(t, MayorSessionName); err != nil {
+		printDownStatus("Mayor", false, err.Error())
+		allOK = false
+	} else {
+		printDownStatus("Mayor", true, "stopped")
+	}
+
+	// 3. Stop Deacon
+	if err := stopSession(t, DeaconSessionName); err != nil {
+		printDownStatus("Deacon", false, err.Error())
+		allOK = false
+	} else {
+		printDownStatus("Deacon", true, "stopped")
+	}
+
+	// 4. Stop Daemon last
+	running, _, _ := daemon.IsRunning(townRoot)
+	if running {
+		if err := daemon.StopDaemon(townRoot); err != nil {
+			printDownStatus("Daemon", false, err.Error())
+			allOK = false
+		} else {
+			printDownStatus("Daemon", true, "stopped")
+		}
+	} else {
+		printDownStatus("Daemon", true, "not running")
+	}
+
+	fmt.Println()
+	if allOK {
+		fmt.Printf("%s All services stopped\n", style.Bold.Render("✓"))
+	} else {
+		fmt.Printf("%s Some services failed to stop\n", style.Bold.Render("✗"))
+		return fmt.Errorf("not all services stopped")
+	}
+
+	return nil
+}
+
+func printDownStatus(name string, ok bool, detail string) {
+	if downQuiet && ok {
+		return
+	}
+	if ok {
+		fmt.Printf("%s %s: %s\n", style.SuccessPrefix, name, style.Dim.Render(detail))
+	} else {
+		fmt.Printf("%s %s: %s\n", style.ErrorPrefix, name, detail)
+	}
+}
+
+// stopSession gracefully stops a tmux session.
+func stopSession(t *tmux.Tmux, sessionName string) error {
+	running, err := t.HasSession(sessionName)
+	if err != nil {
+		return err
+	}
+	if !running {
+		return nil // Already stopped
+	}
+
+	// Try graceful shutdown first (Ctrl-C)
+	if !downForce {
+		_ = t.SendKeysRaw(sessionName, "C-c")
+		time.Sleep(100 * time.Millisecond)
+	}
+
+	// Kill the session
+	return t.KillSession(sessionName)
+}