fix: Remove hardcoded domains

src/lib/components/Actions.svelte

@@ -8,7 +8,7 @@
   import { Separator } from '$/components/ui/separator';
   import * as ToggleGroup from '$/components/ui/toggle-group';
   import { TID } from '$/constants';
-  import { env } from '$/util/env';
+  import { getDomain } from '$/util/util';
   import { browser } from '$app/environment';
   import { waitForRender } from '$lib/util/autoSync';
   import { inputStateStore, stateStore, urlsStore } from '$lib/util/state';
@@ -205,7 +205,10 @@ ${svgString}`);
       <DownloadIcon />
       {text}
     </Button>
-    <ExternalLinkWrapper labelPrefix="Opens your diagram in" domain="mermaid.ink" isVisible={!!url}>
+    <ExternalLinkWrapper
+      labelPrefix="Opens your diagram in"
+      domain={getDomain(url)}
+      isVisible={!!url}>
       <Button class="rounded-l-none" href={url} target="_blank" rel="noreferrer noopener">
         <ExternalLinkIcon />
       </Button>
@@ -238,8 +241,8 @@ ${svgString}`);
       {@render dualActionButton('SVG', onDownloadSVG, $urlsStore.svg)}
       <ExternalLinkWrapper
         labelPrefix="Opens your diagram in"
-        domain="Kroki.io"
-        isVisible={!!env.krokiRendererUrl}>
+        domain={getDomain($urlsStore.kroki)}
+        isVisible={!!$urlsStore.kroki}>
         <a target="_blank" rel="noreferrer" class="flex-grow" href={$urlsStore.kroki}>
           <Button class="action-btn flex w-full items-center gap-2">
             <ExternalLinkIcon /> Kroki
@@ -253,7 +256,7 @@ ${svgString}`);
     {/if}
     <ExternalLinkWrapper
       labelPrefix="Thumbnail generated by"
-      domain="mermaid.ink"
+      domain={getDomain($urlsStore.png)}
       isVisible={!!$urlsStore.mdCode}>
       <CopyInput value={$urlsStore.mdCode} label="Copy Markdown" testID={TID.copyMarkdown} />
     </ExternalLinkWrapper>

src/lib/util/util.ts

@@ -5,6 +5,12 @@ import { applyMigrations } from './migrations';
 import { initURLSubscription, loadState, updateCodeStore, verifyState } from './state';
 import { initAnalytics, plausible } from './stats';
 
+export const getDomain = (url?: string): string => {
+  if (!url) return '';
+  const domain = new URL(url).hostname;
+  return domain;
+};
+
 export const loadStateFromURL = (): void => {
   loadState(window.location.hash.slice(1));
 };