Fix inserted widget runtime to honor external script load order (Leaflet/map rendering)

[Copilot]

Inserted map widgets could render in Preview but fail after insertion because widget JS executed before external library scripts (e.g., Leaflet) were ready. This change aligns inserted-widget runtime behavior with expected browser script ordering so library-dependent widgets initialize reliably.

• Runtime script execution ordering

  • Updated widget.html widget bootstrap to execute injected <script> tags sequentially.
  • For external scripts (src), execution now advances on onload/onerror, then runs source.js only after the injected script queue completes.
  • Added explicit error logging for failed external script loads to improve diagnosability without changing flow control.

• Regression coverage

  • Added tests/unit/widget-runtime.test.ts to assert that source.js observes external library side effects before it runs.

Example of the ordering behavior now enforced:

<!-- source.html -->
<script src="https://unpkg.com/leaflet@1.9.4/dist/leaflet.js"></script>
<div id="map"></div>

// source.js (runs after external scripts finish)
const map = L.map('map').setView([36.5, 128.5], 6);

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• example.com
  • Triggering command: /opt/hostedtoolcache/node/24.14.0/x64/bin/node /opt/hostedtoolcache/node/24.14.0/x64/bin/node -e const sendRequest = require('https').request; const options = { "method": "GET", "headers": { "Accept": "*/*", "Accept-Encoding": "gzip, deflate, br", "Connection": "close", "Origin" saryBeforeUnloadCheckSync,DestroyProfileOnBrowserClose,DialMediaRouteProvider,GlobalMediaControls,HttpsUpgrades,LensOverlay,MediaRouter,PaintHolding,ThirdPartyStoragePartition (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)