Add gt broadcast command to nudge all workers

New command that sends a message to all active workers (polecats + crew).
Supports filtering by rig with --rig flag, and can include infrastructure
agents (mayor, deacon, witness, refinery) with --all flag.

Usage:
  gt broadcast "Check your mail"
  gt broadcast --rig gastown "New work available"
  gt broadcast --all "System maintenance in 5 minutes"
  gt broadcast --dry-run "Test"

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

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

internal/cmd/broadcast.go

@@ -0,0 +1,149 @@
+package cmd
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/style"
+	"github.com/steveyegge/gastown/internal/tmux"
+)
+
+var (
+	broadcastRig    string
+	broadcastAll    bool
+	broadcastDryRun bool
+)
+
+func init() {
+	broadcastCmd.Flags().StringVar(&broadcastRig, "rig", "", "Only broadcast to workers in this rig")
+	broadcastCmd.Flags().BoolVar(&broadcastAll, "all", false, "Include all agents (mayor, witness, etc.), not just workers")
+	broadcastCmd.Flags().BoolVar(&broadcastDryRun, "dry-run", false, "Show what would be sent without sending")
+	rootCmd.AddCommand(broadcastCmd)
+}
+
+var broadcastCmd = &cobra.Command{
+	Use:   "broadcast <message>",
+	Short: "Send a nudge message to all workers",
+	Long: `Broadcasts a message to all active workers (polecats and crew).
+
+By default, only workers (polecats and crew) receive the message.
+Use --all to include infrastructure agents (mayor, deacon, witness, refinery).
+
+The message is sent as a nudge to each worker's Claude Code session.
+
+Examples:
+  gt broadcast "Check your mail"
+  gt broadcast --rig gastown "New priority work available"
+  gt broadcast --all "System maintenance in 5 minutes"
+  gt broadcast --dry-run "Test message"`,
+	Args: cobra.ExactArgs(1),
+	RunE: runBroadcast,
+}
+
+func runBroadcast(cmd *cobra.Command, args []string) error {
+	message := args[0]
+
+	if message == "" {
+		return fmt.Errorf("message cannot be empty")
+	}
+
+	// Get all agent sessions (including polecats)
+	agents, err := getAgentSessions(true)
+	if err != nil {
+		return fmt.Errorf("listing sessions: %w", err)
+	}
+
+	// Filter to target agents
+	var targets []*AgentSession
+	for _, agent := range agents {
+		// Filter by rig if specified
+		if broadcastRig != "" && agent.Rig != broadcastRig {
+			continue
+		}
+
+		// Unless --all, only include workers (crew + polecats)
+		if !broadcastAll {
+			if agent.Type != AgentCrew && agent.Type != AgentPolecat {
+				continue
+			}
+		}
+
+		targets = append(targets, agent)
+	}
+
+	if len(targets) == 0 {
+		fmt.Println("No workers running to broadcast to.")
+		if broadcastRig != "" {
+			fmt.Printf("  (filtered by rig: %s)\n", broadcastRig)
+		}
+		return nil
+	}
+
+	// Dry run - just show what would be sent
+	if broadcastDryRun {
+		fmt.Printf("Would broadcast to %d agent(s):\n\n", len(targets))
+		for _, agent := range targets {
+			fmt.Printf("  %s %s\n", AgentTypeIcons[agent.Type], formatAgentName(agent))
+		}
+		fmt.Printf("\nMessage: %s\n", message)
+		return nil
+	}
+
+	// Send nudges
+	t := tmux.NewTmux()
+	var succeeded, failed int
+	var failures []string
+
+	fmt.Printf("Broadcasting to %d agent(s)...\n\n", len(targets))
+
+	for i, agent := range targets {
+		agentName := formatAgentName(agent)
+
+		if err := t.NudgeSession(agent.Name, message); err != nil {
+			failed++
+			failures = append(failures, fmt.Sprintf("%s: %v", agentName, err))
+			fmt.Printf("  %s %s %s\n", style.ErrorPrefix, AgentTypeIcons[agent.Type], agentName)
+		} else {
+			succeeded++
+			fmt.Printf("  %s %s %s\n", style.SuccessPrefix, AgentTypeIcons[agent.Type], agentName)
+		}
+
+		// Small delay between nudges to avoid overwhelming tmux
+		if i < len(targets)-1 {
+			time.Sleep(100 * time.Millisecond)
+		}
+	}
+
+	fmt.Println()
+	if failed > 0 {
+		fmt.Printf("%s Broadcast complete: %d succeeded, %d failed\n",
+			style.WarningPrefix, succeeded, failed)
+		for _, f := range failures {
+			fmt.Printf("  %s\n", style.Dim.Render(f))
+		}
+		return fmt.Errorf("%d nudge(s) failed", failed)
+	}
+
+	fmt.Printf("%s Broadcast complete: %d agent(s) nudged\n", style.SuccessPrefix, succeeded)
+	return nil
+}
+
+// formatAgentName returns a display name for an agent.
+func formatAgentName(agent *AgentSession) string {
+	switch agent.Type {
+	case AgentMayor:
+		return "mayor"
+	case AgentDeacon:
+		return "deacon"
+	case AgentWitness:
+		return fmt.Sprintf("%s/witness", agent.Rig)
+	case AgentRefinery:
+		return fmt.Sprintf("%s/refinery", agent.Rig)
+	case AgentCrew:
+		return fmt.Sprintf("%s/crew/%s", agent.Rig, agent.AgentName)
+	case AgentPolecat:
+		return fmt.Sprintf("%s/%s", agent.Rig, agent.AgentName)
+	}
+	return agent.Name
+}