fix: correct observation embedding and orphan waiting state

test-fixtures/reference-exhibits/scifi/css/style.css

@@ -2445,9 +2445,37 @@ body.surface-observation > main {
 body.surface-observation .observation-overlay {
   position: fixed;
   inset: 0;
+  /* The NGN pane is already the surface viewport. Do not retain the console
+     overlay's centered 16:9 box, transform, or its outside-pane letterbox. */
+  width: auto;
+  height: auto;
+  transform: none;
+  box-shadow: none;
   z-index: 1;
 }
 
+/* A secondary surface has no authority of its own. This is only shown after
+   its attach request times out; the inactive Observation controls stay hidden. */
+body.surface-observation.surface-waiting::before {
+  content: "WAITING FOR EXHIBIT OWNER\A Observation surface is not connected.";
+  white-space: pre-line;
+  position: fixed;
+  inset: 0;
+  z-index: 2;
+  display: grid;
+  place-items: center;
+  padding: 2rem;
+  box-sizing: border-box;
+  background: #010308;
+  color: var(--tertiary-accent);
+  font-family: var(--mono-font);
+  font-size: clamp(.8rem, 1.4vw, 1.1rem);
+  letter-spacing: .12em;
+  line-height: 1.8;
+  text-align: center;
+  pointer-events: none;
+}
+
 /* Exiting/returning to the console is NGN's job (pane lifecycle), not the
    surface's -- these controls would otherwise mutate the *console's* own
    view.observation overlay flag from a stray click (report SS7/SS8). */

test-fixtures/reference-exhibits/scifi/js/app.js

@@ -337,6 +337,7 @@ document.addEventListener('DOMContentLoaded', () => {
       channelName: XZBTSurfaceMode.channelName(xzbtInstanceId),
       timeoutMs: 1500,
       onSnapshot: (values, stateRevision, registryRevision, presentation) => {
+        document.body.classList.remove('surface-waiting');
         Object.keys(values || {}).forEach(target => applyPresentationState(target, values[target]));
         if (presentation && typeof presentation.tickerText === 'string' && presentation.tickerText) {
           const ticker = document.getElementById('observation-ticker-text');
@@ -368,6 +369,7 @@ document.addEventListener('DOMContentLoaded', () => {
         // No console instance open on this channel (or a stale/unknown
         // ?xi=). Degrade to a clear waiting state rather than inventing
         // local authority (report SS9, Museum's proven behavior).
+        document.body.classList.add('surface-waiting');
         console.warn('[SciFi-XZBT] Observation surface: no console instance found for xi=' + xzbtInstanceId);
       }
     });