Add note about Oauth

src/routes/guides/beatleader-auth/+page.svelte

@@ -150,6 +150,9 @@
       Use the OAuth Login above; we request <code>scp:offline_access</code> to allow refresh without re‑prompting.
     </li>
   </ol>
+  <p>
+    <strong>Multi‑environment setup:</strong> If you deploy to multiple environments (dev, staging, production), you must register <strong>all redirect URIs</strong> in your BeatLeader OAuth application. For example: <code>http://localhost:5173/auth/beatleader/callback</code>, <code>https://staging.example.com/auth/beatleader/callback</code>, and <code>https://example.com/auth/beatleader/callback</code>. The app automatically uses the correct redirect URI based on the current environment's origin.
+  </p>
 
   <h2 id="usage">How this app uses your auth</h2>
   <ul>

src/routes/tools/beatleader-compare/+page.svelte

@@ -523,10 +523,8 @@
                 {/key}
               </div>
             {/if}
-            <div class="mt-3">
-              <SongPlayer hash={item.hash} preferBeatLeader={true} />
-            </div>
-            <div class="mt-3 flex flex-wrap gap-2">
+            <div class="mt-3 flex items-center gap-2">
+              <div class="w-1/2 flex flex-wrap gap-2">
                 <a
                   class="rounded-md border border-white/10 px-2 py-1 text-xs hover:border-white/20"
                   href={item.leaderboardId
@@ -553,6 +551,10 @@
                   title="Copy !bsr"
                 >Copy !bsr</button>
               </div>
+              <div class="w-1/2">
+                <SongPlayer hash={item.hash} preferBeatLeader={true} />
+              </div>
+            </div>
           </div>
         </article>
       {/each}