fix(ui): stale chunk 404 after redeployment — missing Cache-Control on index.html

Problem

After redeploying the goclaw-ui container, users with a cached index.html get:

[ErrorBoundary] TypeError: Failed to fetch dynamically imported module:
https://hq.humanscale.app/assets/login-page-DrRJxksg.js

Root cause: Nginx serves index.html without Cache-Control headers, so browsers may cache it. After a rebuild, Vite generates new chunk hashes — the old index.html references chunks that no longer exist on the server.

Current Mitigations

• lazyWithRetry() in lib/lazy-with-retry.ts retries once then force-reloads with a sessionStorage guard
• Hashed assets in /assets/ are correctly served with Cache-Control: public, immutable

Missing Fix

nginx.conf needs explicit no-cache headers for index.html to prevent browsers from caching the SPA entry point:

location = /index.html {
    add_header Cache-Control "no-cache, no-store, must-revalidate";
    add_header Pragma "no-cache";
    add_header Expires "0";
}

Impact

• Users see a broken page after deploy until they hard-refresh
• lazyWithRetry auto-reload helps but only fires once per session

Start with nginx.conf and inspect how the SPA entry point is served alongside hashed assets. Add the specified no-cache headers for index.html, then verify the response headers after deployment and confirm that a redeployed UI no longer serves a cached entry point referencing missing chunks.