fix(server): HMR WS port interferes between server & desktop

apps/server/src/routes/assets.ts

@@ -6,6 +6,7 @@ import type serveStatic from "serve-static";
 
 import { assetUrlFragment } from "../services/asset_path.js";
 import auth from "../services/auth.js";
+import port from "../services/port.js";
 import { getResourceDir, isDev } from "../services/utils.js";
 import { doubleCsrfProtection as csrfMiddleware } from "./csrf_protection.js";
 
@@ -35,7 +36,15 @@ async function register(app: express.Application) {
         const { createServer: createViteServer } = await import("vite");
         const clientDir = path.join(srcRoot, "../client");
         const vite = await createViteServer({
-            server: { middlewareMode: true },
+            server: {
+                middlewareMode: true,
+                hmr: {
+                    // Derive a unique HMR port from the application port so
+                    // multiple dev instances (e.g. server on 8080, desktop on
+                    // 37742) don't all fight over Vite's default port 24678.
+                    port: port + 10
+                }
+            },
             appType: "spa",
             configFile: path.join(clientDir, "vite.config.mts"),
             base: `/${assetUrlFragment}/`