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/internal/deploy/deploy.go

@@ -0,0 +1,180 @@
+package deploy
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/nats-io/nats.go"
+)
+
+// GameServerStarter abstracts the game server process manager so the deployer
+// can set the executable path and start the server without depending on the
+// concrete process.GameServer type. The existing GameServer will implement
+// UpdatePath in a separate task.
+type GameServerStarter interface {
+	Start() error
+	UpdatePath(path string)
+}
+
+// Deployer orchestrates one-click Rust server deployment. It downloads SteamCMD,
+// installs the Rust Dedicated Server, generates server.cfg, and starts the server
+// process — publishing progress updates to NATS at each stage so the frontend can
+// display real-time deployment status.
+type Deployer struct {
+	nc         *nats.Conn
+	licenseID  string
+	installDir string
+	gameServer GameServerStarter
+}
+
+// NewDeployer creates a new Deployer instance.
+func NewDeployer(nc *nats.Conn, licenseID, installDir string, gs GameServerStarter) *Deployer {
+	return &Deployer{
+		nc:         nc,
+		licenseID:  licenseID,
+		installDir: installDir,
+		gameServer: gs,
+	}
+}
+
+// Deploy executes the full deployment pipeline: SteamCMD install, Rust server
+// download, config generation, and server startup. If any stage fails, a "failed"
+// status is published and the error is returned. Progress updates are published
+// to NATS at each stage transition.
+func (d *Deployer) Deploy(cfg DeployConfig) error {
+	// Stage 1: SteamCMD
+	log.Printf("Deploy: starting SteamCMD installation for license %s", d.licenseID)
+	d.publishStatus("downloading_steamcmd", 0, "Checking for existing SteamCMD installation...")
+
+	steamcmdPath, err := InstallSteamCMD(d.installDir)
+	if err != nil {
+		d.publishStatus("failed", 0, "SteamCMD installation failed", err.Error())
+		return fmt.Errorf("steamcmd install failed: %w", err)
+	}
+
+	log.Printf("Deploy: SteamCMD ready at %s", steamcmdPath)
+	d.publishStatus("downloading_steamcmd", 100, "SteamCMD ready")
+
+	// Stage 2: Download Rust Dedicated Server
+	log.Printf("Deploy: downloading Rust Dedicated Server via SteamCMD")
+	d.publishStatus("downloading_rust", 0, "Downloading Rust Dedicated Server via SteamCMD...")
+
+	if err := DownloadRustServer(steamcmdPath, d.installDir); err != nil {
+		d.publishStatus("failed", 0, "Rust server download failed", err.Error())
+		return fmt.Errorf("rust server download failed: %w", err)
+	}
+
+	log.Printf("Deploy: Rust Dedicated Server installed")
+	d.publishStatus("downloading_rust", 100, "Rust Dedicated Server installed")
+
+	// Stage 3: Generate server.cfg
+	log.Printf("Deploy: generating server.cfg")
+	d.publishStatus("configuring", 0, "Generating server.cfg...")
+
+	if err := GenerateServerCfg(d.installDir, cfg); err != nil {
+		d.publishStatus("failed", 0, "Server configuration failed", err.Error())
+		return fmt.Errorf("config generation failed: %w", err)
+	}
+
+	log.Printf("Deploy: server.cfg written")
+	d.publishStatus("configuring", 100, "Server configured")
+
+	// Stage 4: Start the server
+	log.Printf("Deploy: starting Rust server")
+	d.publishStatus("starting", 0, "Starting Rust server...")
+
+	var exePath string
+	switch runtime.GOOS {
+	case "windows":
+		exePath = filepath.Join(d.installDir, "server", "RustDedicated.exe")
+	default:
+		exePath = filepath.Join(d.installDir, "server", "RustDedicated")
+	}
+
+	d.gameServer.UpdatePath(exePath)
+
+	if err := d.gameServer.Start(); err != nil {
+		d.publishStatus("failed", 0, "Server failed to start", err.Error())
+		return fmt.Errorf("server start failed: %w", err)
+	}
+
+	log.Printf("Deploy: Rust server is now running")
+	d.publishStatus("online", 100, "Rust server is now running")
+
+	return nil
+}
+
+// DownloadRustServer runs SteamCMD to download/update the Rust Dedicated Server
+// (App ID 258550) into {installDir}/server. This function is platform-agnostic —
+// it simply executes the steamcmd binary which was installed by the platform-specific
+// InstallSteamCMD function.
+func DownloadRustServer(steamcmdPath, installDir string) error {
+	serverDir := filepath.Join(installDir, "server")
+
+	log.Printf("Downloading Rust Dedicated Server to %s", serverDir)
+
+	cmd := exec.Command(steamcmdPath,
+		"+login", "anonymous",
+		"+force_install_dir", serverDir,
+		"+app_update", "258550", "validate",
+		"+quit",
+	)
+
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("steamcmd app_update 258550 failed: %w", err)
+	}
+
+	return nil
+}
+
+// CheckServerInstalled returns true if the Rust Dedicated Server executable
+// exists at the expected path within the install directory.
+func CheckServerInstalled(installDir string) bool {
+	var exePath string
+	switch runtime.GOOS {
+	case "windows":
+		exePath = filepath.Join(installDir, "server", "RustDedicated.exe")
+	default:
+		exePath = filepath.Join(installDir, "server", "RustDedicated")
+	}
+
+	_, err := os.Stat(exePath)
+	return err == nil
+}
+
+// publishStatus publishes a DeployStatus message to the NATS subject
+// corrosion.{licenseID}.deploy.status. Publish errors are logged but do not
+// fail the deployment — losing a progress update is not fatal.
+func (d *Deployer) publishStatus(stage string, progress int, message string, errDetail ...string) {
+	subject := fmt.Sprintf("corrosion.%s.deploy.status", d.licenseID)
+
+	status := DeployStatus{
+		Stage:     stage,
+		Progress:  progress,
+		Message:   message,
+		Timestamp: time.Now().UTC().Format(time.RFC3339),
+	}
+
+	if len(errDetail) > 0 && errDetail[0] != "" {
+		status.Error = errDetail[0]
+	}
+
+	data, err := json.Marshal(status)
+	if err != nil {
+		log.Printf("Failed to marshal deploy status: %v", err)
+		return
+	}
+
+	if err := d.nc.Publish(subject, data); err != nil {
+		log.Printf("Failed to publish deploy status to %s: %v", subject, err)
+	}
+}