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/game/CheckScreen.svelte

@@ -5,7 +5,7 @@
   import { t } from '../lib/i18n/index.svelte';
   import { alphabetLetters } from '../lib/alphabet';
   import { canCheckWord, dictionaryLookupUrl, sanitizeCheckWord } from '../lib/checkword';
-  import { telegramOpenExternalLink } from '../lib/telegram';
+  import { onExternalLinkClick } from '../lib/telegram';
   import type { Variant } from '../lib/model';
 
   // Word-check on its own screen: unlimited dictionary lookups, each with a
@@ -58,12 +58,6 @@
       handleError(e);
     }
   }
-  // Inside Telegram, route the dictionary link through the Mini App SDK so Telegram opens it in
-  // its in-app browser instead of the WebView's "open this link?" confirmation; in a plain
-  // browser the anchor's own target=_blank handles it.
-  function openLookup(e: MouseEvent) {
-    if (telegramOpenExternalLink((e.currentTarget as HTMLAnchorElement).href)) e.preventDefault();
-  }
 </script>
 
 <div class="wrap">
@@ -90,7 +84,7 @@
           href={dictionaryLookupUrl(result.word, variant)}
           target="_blank"
           rel="noopener noreferrer"
-          onclick={openLookup}>{t('game.lookup')}</a>
+          onclick={onExternalLinkClick}>{t('game.lookup')}</a>
       {/if}
     </div>
   {/if}