fix(ui): route external links out of the Android VK WebView

The Android VK client's WebView ignores target=_blank and navigates the
Mini App's own window to the target, stranding the player outside the
game with no way back (the dictionary lookup, About/Feedback links, the
ad banner and the bot-link modal fallbacks). vk-bridge 3.x has no method
to open an external URL, so external links are routed through VK's own
leave-VK redirect (vk.com/away.php), which the client intercepts
natively and hands to the system browser.

onExternalLinkClick moves from lib/telegram to a new lib/links that
composes the Telegram and VK routers; iOS and desktop VK open _blank
correctly and are left alone.

ui/src/screens/Feedback.svelte

@@ -7,7 +7,7 @@
   import { connection } from '../lib/connection.svelte';
   import { clientChannel } from '../lib/channel';
   import { attachmentError, linkify, MAX_BODY } from '../lib/feedback';
-  import { onExternalLinkClick } from '../lib/telegram';
+  import { onExternalLinkClick } from '../lib/links';
   import type { FeedbackState } from '../lib/model';
 
   // The feedback screen: a message (+ optional single attachment) the player sends to