seat tray: tray.js, SCSS, FTs, Jasmine specs

- new apps.epic.static tray.js: IIFE with drag-open/click-close/wobble
  behaviour; document-level pointermove+mouseup listeners; reset() for
  Jasmine afterEach; try/catch around setPointerCapture for synthetic events
- _room.scss: #id_tray_wrap fixed-right flex container; #id_tray_handle +
  #id_tray_grip (box-shadow frame, transparent inner window, border-radius
  clip); #id_tray_btn grab cursor; #id_tray bevel box-shadows, margin-left
  gap, height removed (align-items:stretch handles it); tray-wobble keyframes
- _applets.scss + _game-kit.scss: z-index raised (312-318) for primacy over
  tray (310)
- room.html: #id_tray_wrap + children markup; tray.js script tag
- FTs test_room_tray: 5 tests (T1-T5); _simulate_drag via execute_script
  pointer events (replaces unreliable ActionChains drag); wobble asserts on
  #id_tray_wrap not btn
- static_src/tests/TraySpec.js + SpecRunner.html: Jasmine unit tests for
  all tray.js branches

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/templates/apps/gameboard/room.html

@@ -100,6 +100,15 @@
         {% if not room.table_status and room.gate_status != "RENEWAL_DUE" %}
             {% include "apps/gameboard/_partials/_gatekeeper.html" %}
         {% endif %}
+        <div id="id_tray_wrap">
+            <div id="id_tray_handle">
+                <div id="id_tray_grip"></div>
+                <button id="id_tray_btn" aria-label="Open seat tray">
+                    <i class="fa-solid fa-dice-d20"></i>
+                </button>
+            </div>
+            <div id="id_tray" style="display:none"></div>
+        </div>
         {% include "apps/gameboard/_partials/_room_gear.html" %}
     </div>
 {% endblock content %}
@@ -109,4 +118,5 @@
     <script src="{% static 'apps/epic/gatekeeper.js' %}"></script>
     <script src="{% static 'apps/epic/role-select.js' %}"></script>
     <script src="{% static 'apps/epic/sig-select.js' %}"></script>
+    <script src="{% static 'apps/epic/tray.js' %}"></script>
 {% endblock scripts %}