feat(ui): route all in-app external links through Telegram openLink

Extend the openLink routing from the dictionary lookup to every external
link shown inside the Mini App, so none triggers the WebView's 'open this
link?' confirmation. A shared onExternalLinkClick handler resolves the anchor
via closest() (so it also works delegated on {@html} content), backed by a
pure routeExternalLinkInTelegram decision: only inside Telegram, only an
external http(s) target=_blank link, excluding same-origin/in-app and t.me
links (t.me keeps openTelegramLink). Applied to the word-check lookup, the
About rules link, the Feedback operator-reply links, and the feature-gated
announcement banner.

Outside Telegram every anchor keeps its native target=_blank.

ui/src/components/AdBanner.svelte

@@ -9,6 +9,7 @@
     type BannerConfig,
     type BannerItem,
   } from '../lib/banner';
+  import { onExternalLinkClick } from '../lib/telegram';
 
   let { items = mockBanners(), config = defaultBannerConfig }: { items?: BannerItem[]; config?: BannerConfig } =
     $props();
@@ -39,7 +40,11 @@
   onDestroy(() => rotator?.stop());
 </script>
 
-<div class="ad" bind:this={viewport}>
+<!-- The banner links are rendered via {@html}; a delegated click routes any of them through the
+     Telegram SDK (onExternalLinkClick uses closest('a')) so they skip the WebView confirmation. -->
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<!-- svelte-ignore a11y_click_events_have_key_events -->
+<div class="ad" bind:this={viewport} onclick={onExternalLinkClick}>
   {#key current}
     <div
       class="track"