Surface destination edits as the core dynamic short-link feature.

Move destination editing to the top of the link page, clarify that the short URL never changes, prevent caches from pinning old redirects, and test that later destination updates take effect immediately.

app/Http/Controllers/Link/LinkController.php

@@ -116,7 +116,11 @@ class LinkController extends Controller
             return back()->withInput()->withErrors(['destination_url' => $e->getMessage()]);
         }
 
-        return back()->with('success', 'Link updated.');
+        $message = isset($validated['destination_url'])
+            ? 'Destination updated. Your short link is unchanged — new clicks go to the new URL.'
+            : 'Link updated.';
+
+        return back()->with('success', $message);
     }
 
     public function destroy(ShortLink $link): RedirectResponse