feat(kez-chat/web): route new accounts to /welcome onboarding checklist

New-account success screen sent users straight to /chats; first-run users
never saw the Getting Started checklist. Route to /welcome instead.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

kez-chat/web/src/routes/CreateAccount.svelte

@@ -265,9 +265,9 @@
       </p>
       <button
         class="mt-4 px-4 py-2 bg-accent text-accent-contrast rounded-md hover:bg-accent-dim"
-        onclick={() => push("/chats")}
+        onclick={() => push("/welcome")}
       >
-        Go to dashboard
+        Get started →
       </button>
     </div>
   {/if}