Add NodeCG preflight step and sanity script

src/main/nodecg/process-manager.ts

@@ -30,6 +30,7 @@ type NodecgProcessManagerDeps = {
 };
 
 export type NodecgProcessManager = {
+  runPreflightChecks: () => Promise<void>;
   startNodecgProcess: () => Promise<ChildProcess>;
   waitForNodecgReady: (startTime: number) => Promise<void>;
   stopNodecgProcessGracefully: () => Promise<void>;
@@ -51,7 +52,7 @@ export function createNodecgProcessManager({
   let lastExit: { code: number | null; signal: NodeJS.Signals | null } | null = null;
   let lastStderrLine: string | null = null;
 
-  const startNodecgProcess = async (): Promise<ChildProcess> => {
+  const runPreflightChecks = async (): Promise<void> => {
     validateNodecgInstall(
       nodecgRootPath,
       resolvedDeps.platform,
@@ -66,6 +67,10 @@ export function createNodecgProcessManager({
         `Port ${appConfig.nodecgPort} is already in use. Stop the process using it or set NODECG_PORT before starting.`,
       );
     }
+  };
+
+  const startNodecgProcess = async (): Promise<ChildProcess> => {
+    await runPreflightChecks();
 
     const command = resolvedDeps.platform === "win32" ? "npx.cmd" : "npx";
     const child = resolvedDeps.spawnProcess(command, ["nodecg", "start"], {
@@ -186,6 +191,7 @@ export function createNodecgProcessManager({
   };
 
   return {
+    runPreflightChecks,
     startNodecgProcess,
     waitForNodecgReady,
     stopNodecgProcessGracefully,