feat(frontend): bundle the icons so the app works offline

Every <wa-icon> was fetched from ka-f.fontawesome.com at runtime —
confirmed from `performance.getEntriesByType('resource')`, 36 requests
— so offline the app had no icons at all. `setBasePath()` does not
affect the icon resolver; only the component autoloader reads it.
Overriding Web Awesome's `default` icon library fixes all 165 call
sites without changing one of them. Cross-origin requests at startup:
22 -> 0.

Three things about it are load-bearing. The set is Font Awesome Free
(CC BY 4.0, vendored with its licence by `scripts/fetch-icons.mjs`)
because the kit CDN serves Pro, which cannot be redistributed. The
names are a committed list rather than anything derived, because
twenty call sites compute their icon name from state and no static
pass can enumerate them. And a name that is not bundled is reported at
runtime to `window.__yjIconMisses` and drawn as a fallback, since a
missing icon used to be impossible — the CDN having had everything.

frontend/src/assets/icons/fa/solid/database.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 7.3.1 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2026 Fonticons, Inc. --><path fill="currentColor" d="M448 205.8c-14.8 9.8-31.8 17.7-49.5 24-47 16.8-108.7 26.2-174.5 26.2S96.4 246.5 49.5 229.8c-17.6-6.3-34.7-14.2-49.5-24L0 288c0 44.2 100.3 80 224 80s224-35.8 224-80l0-82.2zm0-77.8l0-48C448 35.8 347.7 0 224 0S0 35.8 0 80l0 48c0 44.2 100.3 80 224 80s224-35.8 224-80zM398.5 389.8C351.6 406.5 289.9 416 224 416S96.4 406.5 49.5 389.8c-17.6-6.3-34.7-14.2-49.5-24L0 432c0 44.2 100.3 80 224 80s224-35.8 224-80l0-66.2c-14.8 9.8-31.8 17.7-49.5 24z"/></svg>