feat(04-02): i3bar widget with per-session colors, workspace prefix, wait type and duration

- One i3bar block per session (individual colors: red/green/gray)
- Workspace prefix: 10-vmux[W], 3-auth[? 3m]
- Wait type markers: ⚡ permission, ? question, ! generic
- Wait duration: [⚡ 30s], [? 3m], [? 1h15m]
- Standalone mode only (separate bar, no i3status wrapping)
- Removed isTerminal and i3status wrapping code

main.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -147,11 +146,7 @@ func main() {
 			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
 			os.Exit(1)
 		}
-		i3statusCmd := ""
-		if _, err := exec.LookPath("i3status"); err == nil {
-			i3statusCmd = "i3status"
-		}
-		runI3Bar(sockPath, i3statusCmd)
+		runI3Bar(sockPath)
 
 	case "daemon":
 		runDaemon(sockPath)
@@ -203,6 +198,7 @@ func (p *realI3TreeProvider) GetTree() (i3.Tree, error) {
 	return i3.GetTree()
 }
 
+
 func printUsage() {
 	fmt.Fprintf(os.Stderr, `Usage: vmux <command> [args...]