feat(panel): move Altitude to the top of the panel (mobile: reachable with video on screen)

On mobile the panel wraps below the (sticky) stage; putting the Altitude knob
first means it sits right under the video instead of behind Output + knobs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

simulator/static/index.html

@@ -65,6 +65,16 @@
 
     <section class="panel">
       <div id="sr-status" class="visually-hidden" role="status" aria-live="polite"></div>
+      <fieldset>
+        <legend data-i18n="altitude.legend">Altitude</legend>
+        <div class="dial-wrap">
+          <svg id="dial" viewBox="0 0 100 100" role="slider" tabindex="0"
+               aria-label="Altitude — turn or use arrow keys to change scale"
+               aria-valuemin="0" aria-valuenow="0" aria-valuetext="cosmos"></svg>
+        </div>
+        <span id="scale-name" class="scale-name">—</span>
+      </fieldset>
+
       <fieldset>
         <legend data-i18n="output.legend">Output</legend>
         <label class="dev-switch" for="visual">
@@ -103,16 +113,6 @@
         <label><span data-i18n="knobs.mood">Mood — dark ◀ 0 ▶ light</span> <input type="range" id="mood" min="-4" max="4" value="0" /></label>
       </fieldset>
 
-      <fieldset>
-        <legend data-i18n="altitude.legend">Altitude</legend>
-        <div class="dial-wrap">
-          <svg id="dial" viewBox="0 0 100 100" role="slider" tabindex="0"
-               aria-label="Altitude — turn or use arrow keys to change scale"
-               aria-valuemin="0" aria-valuenow="0" aria-valuetext="cosmos"></svg>
-        </div>
-        <span id="scale-name" class="scale-name">—</span>
-      </fieldset>
-
       <!-- Dev Mode: a single toggle; everything dev (pool picker + analysis) lives below it. -->
       <label class="dev-switch" for="dev-mode">
         <input type="checkbox" id="dev-mode" />