Wire antidriftd daemon entrypoint

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cmd/antidriftd/main.go

@@ -1,7 +1,59 @@
+// Command antidriftd is the AntiDrift focus daemon: it serves a local web UI
+// and owns the commitment state machine.
 package main
 
-import "fmt"
+import (
+	"log"
+	"os/exec"
+	"runtime"
+	"time"
+
+	"antidrift/internal/session"
+	"antidrift/internal/store"
+	"antidrift/internal/web"
+)
+
+const addr = "localhost:7777"
 
 func main() {
-	fmt.Println("antidriftd")
+	path, err := store.DefaultPath()
+	if err != nil {
+		log.Fatalf("resolve snapshot path: %v", err)
+	}
+	ctrl, err := session.New(path)
+	if err != nil {
+		log.Fatalf("load session: %v", err)
+	}
+
+	srv := web.NewServer(ctrl)
+	srv.Init() // re-arm or expire a restored Active session
+
+	go openBrowser("http://" + addr)
+
+	log.Printf("antidriftd listening on http://%s", addr)
+	if err := srv.Router().Run(addr); err != nil {
+		log.Fatalf("server: %v", err)
+	}
+}
+
+// openBrowser best-effort launches the default browser after a short delay so
+// the server is listening first. Failures are logged, not fatal.
+func openBrowser(url string) {
+	time.Sleep(300 * time.Millisecond)
+	var cmd string
+	var args []string
+	switch runtime.GOOS {
+	case "linux":
+		cmd, args = "xdg-open", []string{url}
+	case "darwin":
+		cmd, args = "open", []string{url}
+	case "windows":
+		cmd, args = "rundll32", []string{"url.dll,FileProtocolHandler", url}
+	default:
+		log.Printf("open browser manually: %s", url)
+		return
+	}
+	if err := exec.Command(cmd, args...).Start(); err != nil {
+		log.Printf("could not open browser (%v); visit %s", err, url)
+	}
 }