fix: enforce first-frame timeout and nav labels

src/scene/world/environment.ts

@@ -121,6 +121,7 @@ export async function createProceduralSceneGeneration(
   let lastNow: number | null = null;
   let disposed = false;
   let renderedFrames = 0;
+  let firstFrameSuppressionRecorded = false;
 
   const resize = (): void => {
     const nextWidth = Math.max(1, canvas.clientWidth || canvas.width || 1);
@@ -145,6 +146,13 @@ export async function createProceduralSceneGeneration(
   return {
     render(snapshot: Readonly<JourneySnapshot>, now: number) {
       if (disposed) return;
+      if (TEST_BUILD && isTestFault('F2-first-frame-timeout')) {
+        if (!firstFrameSuppressionRecorded) {
+          firstFrameSuppressionRecorded = true;
+          recordTestFaultEvent('first-frame-suppressed');
+        }
+        return false;
+      }
       if (
         TEST_BUILD
         && isTestFault('F3-post-first-frame-exception')