Phase 0: fix typecheck, format, build; remove stray emit; pin port via env

apps/api/src/ws.ts

@@ -6,33 +6,48 @@
  *
  * Phase 1 will wire this to a Redis pubsub channel so multiple API
  * instances can share the fan-out load.
+ *
+ * Hono's @hono/node-ws gives us a `WSContext` that wraps a `ws` WebSocket
+ * with extra Hono-specific methods. We use a thin adapter type so this
+ * module doesn't need to import from hono.
  */
 import type { LiveMessage } from '@kerbal-rt/shared-types';
-import type { WebSocket } from 'ws';
 
-const clients = new Set<WebSocket>();
+/** Anything with .send(string) and a .readyState we can inspect. */
+export interface WsLike {
+  send(data: string): void;
+  readonly readyState: number;
+}
 
-function send(ws: WebSocket, msg: LiveMessage): void {
-  if (ws.readyState === 1 /* OPEN */) {
+const READY_STATE_OPEN = 1;
+const clients = new Set<WsLike>();
+
+function send(ws: WsLike, msg: LiveMessage): void {
+  if (ws.readyState === READY_STATE_OPEN) {
     ws.send(JSON.stringify(msg));
   }
 }
 
 export const handleLiveSocket = {
-  onOpen(ws: WebSocket): void {
+  onOpen(ws: WsLike): void {
     clients.add(ws);
   },
 
-  onMessage(_evt: { data: unknown }, _ws: WebSocket): void {
+  onMessage(_evt: { data: unknown }, _ws: WsLike): void {
     // Phase 0: clients are read-only, ignore incoming.
     // Phase 2: accept subscriptions like { type: 'subscribe', vesselId: '...' }
   },
 
-  onClose(ws: WebSocket): void {
+  onClose(ws: WsLike): void {
     clients.delete(ws);
   },
 
   broadcast(msg: LiveMessage): void {
     for (const ws of clients) send(ws, msg);
   },
+
+  /** For tests / introspection. */
+  get clientCount(): number {
+    return clients.size;
+  },
 };