fix(statusline): limit max rigs displayed to prevent overflow

When many rigs are registered, the tmux statusline would truncate or
overflow. This adds a configurable maximum (default 5) with an overflow
indicator showing how many rigs are hidden (e.g., "+3").

Running rigs are prioritized (shown first) due to existing sort order.

Configure via GT_MAX_RIGS_DISPLAY env var:
- Default: 5 rigs shown
- Set to 0 for unlimited
- Set to any positive number for custom limit

Fixes: h-4wtnc

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

internal/cmd/statusline.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"strings"
 
 	"github.com/spf13/cobra"
@@ -320,6 +321,20 @@ func runMayorStatusLine(t *tmux.Tmux) error {
 		return rigs[i].name < rigs[j].name
 	})
 
+	// Truncate to max rigs if there are too many to display
+	// Default: 5, configurable via GT_MAX_RIGS_DISPLAY env var (0 = unlimited)
+	maxRigs := 5
+	if envMax := os.Getenv("GT_MAX_RIGS_DISPLAY"); envMax != "" {
+		if parsed, err := strconv.Atoi(envMax); err == nil && parsed >= 0 {
+			maxRigs = parsed
+		}
+	}
+	overflow := 0
+	if maxRigs > 0 && len(rigs) > maxRigs {
+		overflow = len(rigs) - maxRigs
+		rigs = rigs[:maxRigs]
+	}
+
 	// Build display with group separators
 	var rigParts []string
 	var lastGroup string
@@ -366,6 +381,11 @@ func runMayorStatusLine(t *tmux.Tmux) error {
 		rigParts = append(rigParts, led+space+rig.name)
 	}
 
+	// Add overflow indicator if rigs were truncated
+	if overflow > 0 {
+		rigParts = append(rigParts, fmt.Sprintf("+%d", overflow))
+	}
+
 	if len(rigParts) > 0 {
 		parts = append(parts, strings.Join(rigParts, " "))
 	}