Revert EMULATOR_MODE to rcon default, restore RCON config

.env.example

@@ -46,8 +46,11 @@ DB_BACKUP_KEEP=7
 # Minutes between repeat health-fail alerts from jobs-worker (default 15).
 HEALTH_ALERT_COOLDOWN_MIN=15
 
-# --- EMULATOR API ---
-EMULATOR_API_URL=http://127.0.0.1:3001
+# --- RCON (Low Latency Loop) ---
+RCON_HOST=127.0.0.1
+RCON_PORT=3003
+EMU_PORT=3004
+RCON_TIMEOUT_MS=2000
 
 # --- EMAIL & NOTIFICATIONS ---
 SMTP_HOST=

src/env.ts

@@ -40,11 +40,17 @@ const schema = z
 		SMTP_USER: z.string().optional(),
 		SMTP_PASSWORD: z.string().optional(),
 		SMTP_FROM: z.string().optional(),
-		// Emulator transport selection. "api" uses an HTTP endpoint that accepts the same
+		// RCON link to the Arcturus emulator (raw-JSON TCP protocol).
+		RCON_HOST: z.string().default("127.0.0.1"),
+		RCON_PORT: z.coerce.number().int().positive().default(3001),
+		RCON_TIMEOUT_MS: z.coerce.number().int().positive().default(10_000),
+		RCON_MAX_RETRIES: z.coerce.number().int().positive().default(3),
+		// Emulator transport selection. "rcon" uses the raw-JSON TCP protocol
+		// above; "api" uses an HTTP endpoint that accepts the same
 		// `{"key":...,"data":...}` payload (for emulators without RCON).
-		EMULATOR_MODE: z.enum(["rcon", "api"]).default("api"),
+		EMULATOR_MODE: z.enum(["rcon", "api"]).default("rcon"),
 		// HTTP endpoint used when EMULATOR_MODE=api. Required in that mode.
-		EMULATOR_API_URL: z.string().url(),
+		EMULATOR_API_URL: z.string().url().optional(),
 		// Optional bearer/key auth for the API transport. When set, it is sent
 		// as `${EMULATOR_API_KEY_HEADER}: ${EMULATOR_API_KEY}` (default header
 		// "Authorization").

src/lib/services/alert.ts

@@ -223,8 +223,10 @@ export function emulatorOffline(detail?: string): Promise<SendAlertResult> {
 		severity: "critical",
 		message: detail
 			? `Emulator appears offline: ${detail}`
-			: "Emulator appears offline — emulator API connection could not be established.",
+			: "Emulator appears offline — RCON connection could not be established.",
 		context: {
+			rconHost: env.RCON_HOST,
+			rconPort: env.RCON_PORT,
 			...(detail ? { detail } : {}),
 		},
 	});

src/lib/services/rcon.ts

@@ -225,20 +225,24 @@ export function httpTransport(opts: {
  * misconfiguration surfaces immediately instead of on first command.
  */
 export function createEmulatorTransport(): RconTransport {
-	const mode = env.EMULATOR_MODE ?? "api";
-	if (mode === "api") {
+	if (env.EMULATOR_MODE === "api") {
+		if (!env.EMULATOR_API_URL) {
+			throw new Error("EMULATOR_MODE=api requires EMULATOR_API_URL to be set");
+		}
 		return httpTransport({
-			url: env.EMULATOR_API_URL ?? "http://127.0.0.1:3001",
-			timeoutMs: 10_000,
+			url: env.EMULATOR_API_URL,
+			timeoutMs: env.RCON_TIMEOUT_MS,
 			apiKey: env.EMULATOR_API_KEY,
 			apiKeyHeader: env.EMULATOR_API_KEY_HEADER,
-			maxRetries: 3,
+			maxRetries: env.RCON_MAX_RETRIES,
 		});
 	}
-	// API mode only; RCON transport removed.
-	throw new Error(
-		"EMULATOR_MODE=rcon is no longer supported; use EMULATOR_MODE=api",
-	);
+	return tcpTransport({
+		host: env.RCON_HOST,
+		port: env.RCON_PORT,
+		timeoutMs: env.RCON_TIMEOUT_MS,
+		maxRetries: env.RCON_MAX_RETRIES,
+	});
 }
 
 const globalForRcon = globalThis as unknown as { rcon?: RconClient };