Broaden dev CORS to any localhost port

skyai-cloud's Vite dev server hops ports (5173 -> 5174 -> ...) when one
is taken, so a fixed localhost:5173 allowlist breaks the browser's
cross-origin calls. Allow any http://localhost:<port> in dev; the
*.sky-ai.com rule is unchanged for deployed origins.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/arcadia_cloud_web/endpoint.ex

@@ -48,7 +48,8 @@ defmodule ArcadiaCloudWeb.Endpoint do
 
   plug CORSPlug,
     origin: [
-      "http://localhost:5173",
+      # any localhost port — Vite dev servers hop ports when one is taken
+      ~r{^http://localhost:\d+$},
       ~r{^https://.*\.sky-ai\.com$}
     ]