feat(dnd): Add notification level control (gt-xmsme)

Implements Do Not Disturb mode for Gas Town agents:

- Add notification_level to agent bead schema (verbose, normal, muted)
- gt dnd [on|off|status] - quick toggle for DND mode
- gt notify [verbose|normal|muted] - fine-grained control
- gt nudge checks target DND status, skips if muted
- --force flag on nudge to override DND

This allows agents (especially Mayor) to mute notifications
during focused work like swarm coordination.

Generated with Claude Code

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

internal/cmd/dnd.go

@@ -0,0 +1,129 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/beads"
+	"github.com/steveyegge/gastown/internal/style"
+	"github.com/steveyegge/gastown/internal/workspace"
+)
+
+var dndCmd = &cobra.Command{
+	Use:     "dnd [on|off|status]",
+	GroupID: GroupComm,
+	Short:   "Toggle Do Not Disturb mode for notifications",
+	Long: `Control notification level for the current agent.
+
+Do Not Disturb (DND) mode mutes non-critical notifications,
+allowing you to focus on work without interruption.
+
+Subcommands:
+  on      Enable DND mode (mute notifications)
+  off     Disable DND mode (resume normal notifications)
+  status  Show current notification level
+
+Without arguments, toggles DND mode.
+
+Related: gt notify - for fine-grained notification level control`,
+	Args: cobra.MaximumNArgs(1),
+	RunE: runDnd,
+}
+
+func init() {
+	rootCmd.AddCommand(dndCmd)
+}
+
+func runDnd(cmd *cobra.Command, args []string) error {
+	// Get current agent bead ID
+	cwd, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("getting current directory: %w", err)
+	}
+
+	townRoot, err := workspace.FindFromCwdOrError()
+	if err != nil {
+		return fmt.Errorf("not in a Gas Town workspace: %w", err)
+	}
+
+	roleInfo, err := GetRoleWithContext(cwd, townRoot)
+	if err != nil {
+		return fmt.Errorf("determining role: %w", err)
+	}
+
+	ctx := RoleContext{
+		Role:     roleInfo.Role,
+		Rig:      roleInfo.Rig,
+		Polecat:  roleInfo.Polecat,
+		TownRoot: townRoot,
+		WorkDir:  cwd,
+	}
+
+	agentBeadID := getAgentBeadID(ctx)
+	if agentBeadID == "" {
+		return fmt.Errorf("could not determine agent bead ID for role %s", roleInfo.Role)
+	}
+
+	bd := beads.New(townRoot)
+
+	// Get current level
+	currentLevel, err := bd.GetAgentNotificationLevel(agentBeadID)
+	if err != nil {
+		// Agent bead might not exist yet - default to normal
+		currentLevel = beads.NotifyNormal
+	}
+
+	// Determine action
+	var action string
+	if len(args) == 0 {
+		// Toggle: if muted -> normal, else -> muted
+		if currentLevel == beads.NotifyMuted {
+			action = "off"
+		} else {
+			action = "on"
+		}
+	} else {
+		action = args[0]
+	}
+
+	switch action {
+	case "on":
+		if err := bd.UpdateAgentNotificationLevel(agentBeadID, beads.NotifyMuted); err != nil {
+			return fmt.Errorf("enabling DND: %w", err)
+		}
+		fmt.Printf("%s DND enabled - notifications muted\n", style.SuccessPrefix)
+		fmt.Printf("  Run %s to resume notifications\n", style.Bold.Render("gt dnd off"))
+
+	case "off":
+		if err := bd.UpdateAgentNotificationLevel(agentBeadID, beads.NotifyNormal); err != nil {
+			return fmt.Errorf("disabling DND: %w", err)
+		}
+		fmt.Printf("%s DND disabled - notifications resumed\n", style.SuccessPrefix)
+
+	case "status":
+		levelDisplay := currentLevel
+		if levelDisplay == "" {
+			levelDisplay = beads.NotifyNormal
+		}
+
+		icon := "🔔"
+		description := "All important notifications"
+		switch levelDisplay {
+		case beads.NotifyVerbose:
+			icon = "🔊"
+			description = "All notifications (verbose)"
+		case beads.NotifyMuted:
+			icon = "🔕"
+			description = "Notifications muted (DND)"
+		}
+
+		fmt.Printf("%s Notification level: %s\n", icon, style.Bold.Render(levelDisplay))
+		fmt.Printf("  %s\n", style.Dim.Render(description))
+
+	default:
+		return fmt.Errorf("unknown action %q: use on, off, or status", action)
+	}
+
+	return nil
+}