feat: Add companion agent one-click deployment + fix frontend TS errors

Go deployment orchestrator with platform-specific SteamCMD install,
Rust server download, server.cfg generation, and service registration.
Wire deploy command subscription in daemon, make GameServerPath optional,
add InstallDir config with OS-aware defaults. Fix unused imports and
WebSocket subscribe API in ServerView.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

companion-agent/cmd/agent/main.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"runtime"
 	"syscall"
 	"time"
 
@@ -24,9 +25,12 @@ type Config struct {
 
 	// Game server configuration
 	SteamCMDPath   string `envconfig:"STEAMCMD_PATH" default:"/usr/games/steamcmd"`
-	GameServerPath string `envconfig:"GAME_SERVER_PATH" required:"true"`
+	GameServerPath string `envconfig:"GAME_SERVER_PATH" default:""`
 	GameServerArgs string `envconfig:"GAME_SERVER_ARGS" default:"-batchmode"`
 
+	// Install directory for deployment
+	InstallDir string `envconfig:"INSTALL_DIR" default:""`
+
 	// Optional settings
 	HeartbeatInterval int `envconfig:"HEARTBEAT_INTERVAL" default:"60"`
 	LogLevel          string `envconfig:"LOG_LEVEL" default:"info"`
@@ -44,11 +48,21 @@ func main() {
 		log.Fatalf("Failed to load configuration: %v", err)
 	}
 
+	// Set default InstallDir based on OS if not configured
+	if cfg.InstallDir == "" {
+		if runtime.GOOS == "windows" {
+			cfg.InstallDir = `C:\RustServer`
+		} else {
+			cfg.InstallDir = "/opt/rustserver"
+		}
+	}
+
 	log.Printf("Configuration loaded:")
 	log.Printf("  NATS URL: %s", cfg.NATSUrl)
 	log.Printf("  License ID: %s", cfg.LicenseID)
 	log.Printf("  Game Server Path: %s", cfg.GameServerPath)
 	log.Printf("  SteamCMD Path: %s", cfg.SteamCMDPath)
+	log.Printf("  Install Dir: %s", cfg.InstallDir)
 	log.Printf("  Heartbeat Interval: %ds", cfg.HeartbeatInterval)
 
 	// Create context with signal handling for graceful shutdown
@@ -73,6 +87,7 @@ func main() {
 		GameServerPath:    cfg.GameServerPath,
 		GameServerArgs:    cfg.GameServerArgs,
 		Version:           version,
+		InstallDir:        cfg.InstallDir,
 	}
 
 	// Start daemon