Include HTML files and register service worker for wasm sample

[Copilot]

The Sourcetrail project config omitted .html, preventing HTML assets from appearing when browsing wallet_core.srctrlprj, and the wasm sample lacked a service worker for offline/cache handling.

• Configuration
  • Added .html to <source_extensions> in wallet_core.srctrlprj so HTML files are indexed for viewing.
• Wasm sample
  • Registered a service worker in samples/wasm/index.html with success/error logging.
  • Added samples/wasm/service-worker.js (cache-first fetch with offline fallback) and updated .gitignore to include it.

Example:

<source_extensions>
    <source_extension>.cpp</source_extension>
    <source_extension>.cxx</source_extension>
    <source_extension>.cc</source_extension>
    <source_extension>.html</source_extension>
</source_extensions>

Original prompt

On wallet_core.srctrlprj, view html

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@copilot register service worker

[Copilot]

@copilot register service worker

Service worker is now registered in the wasm sample with cache-first handling and offline fallback (69b7f36).