Add Temporal worker and test client programs

Creates:
- cmd/worker/main.go: Worker that registers workflows and activities
- cmd/test-workflow/main.go: Test client to trigger workflows

Adds go.temporal.io/sdk dependency to go.mod.

cmd/worker/main.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"go.temporal.io/sdk/client"
+	"go.temporal.io/sdk/worker"
+	"github.com/Riotpiaole/homelab-frontend/internal/workflow"
+)
+
+func main() {
+	hostPort := flag.String("host", "temporal.temporal:7233", "Temporal server host:port")
+	namespace := flag.String("namespace", "production", "Temporal namespace")
+	taskQueue := flag.String("queue", "worker-production", "Task queue")
+	flag.Parse()
+
+	// Connect to Temporal server
+	c, err := client.Dial(client.Options{
+		HostPort:  *hostPort,
+		Namespace: *namespace,
+	})
+	if err != nil {
+		log.Fatalf("Failed to connect to Temporal: %v", err)
+	}
+	defer c.Close()
+
+	log.Printf("Connected to Temporal at %s (namespace: %s)", *hostPort, *namespace)
+
+	// Create worker
+	w := worker.New(c, *taskQueue, worker.Options{})
+
+	// Register workflows
+	w.RegisterWorkflow(workflow.HelloWorldWorkflow)
+	w.RegisterWorkflow(workflow.GreeterWorkflow)
+	w.RegisterWorkflow(workflow.ProcessOrderWorkflow)
+
+	// Register activities
+	w.RegisterActivity(workflow.GreetActivity)
+	w.RegisterActivity(workflow.ValidateOrderActivity)
+	w.RegisterActivity(workflow.ProcessPaymentActivity)
+	w.RegisterActivity(workflow.NotifyCustomerActivity)
+
+	log.Printf("Starting worker on task queue: %s", *taskQueue)
+
+	// Handle graceful shutdown
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	go func() {
+		<-sigChan
+		log.Println("Shutting down worker...")
+		w.Stop()
+	}()
+
+	// Run worker (blocks)
+	if err := w.Run(worker.InterruptCh()); err != nil {
+		log.Fatalf("Worker error: %v", err)
+	}
+}