fix(mobile): Android no longer freezes when you go back from a running thread

apps/mobile/package.json

@@ -174,7 +174,8 @@
   },
   "reanimated": {
     "staticFeatureFlags": {
-      "DISABLE_COMMIT_PAUSING_MECHANISM": true
+      "DISABLE_COMMIT_PAUSING_MECHANISM": true,
+      "ANDROID_SYNCHRONOUSLY_UPDATE_UI_PROPS": true
     }
   }
 }

apps/mobile/src/components/LoadingStrip.tsx

@@ -56,21 +56,25 @@ function IndeterminateLoadingStrip() {
     };
   }, [travelProgress]);
 
+  // Keep the animated style transform-only. On Android a layout prop here would
+  // make every frame a shadow-tree commit instead of a synchronous UI update.
   const indicatorStyle = useAnimatedStyle(
     () => ({
       transform: [
         {
           translateX: (containerWidth + indicatorWidth) * travelProgress.value - indicatorWidth,
         },
       ],
-      width: indicatorWidth,
     }),
     [containerWidth, indicatorWidth],
   );
 
   return (
     <LoadingStripFrame onLayout={setContainerWidth}>
-      <Animated.View className="h-full rounded-full bg-primary" style={indicatorStyle} />
+      <Animated.View
+        className="h-full rounded-full bg-primary"
+        style={[{ width: indicatorWidth }, indicatorStyle]}
+      />
     </LoadingStripFrame>
   );
 }

docs/internals/performance-regressions.md

@@ -102,3 +102,16 @@ continuous traffic during an outage.
 Focused coverage: `ProjectionSettlement.test.ts`, `ThreadSettlementService.test.ts`,
 `runtimeLayer.test.ts`, `AgentAwarenessRelay.test.ts`, `GitVcsDriverCore.test.ts`,
 `ThreadStatusIndicators.subscriptions.test.tsx`, and `desktopLocal.test.ts`.
+
+## Mobile looping animations
+
+`apps/mobile/package.json` sets Reanimated's `DISABLE_COMMIT_PAUSING_MECHANISM` so keyboard
+avoiding animates on iOS. Without commit pausing, an animation that commits to the shadow tree on every frame
+can starve React's commits: the JS thread retries the same commit until it gives up, which looks
+like a frozen screen where back does nothing. Release builds spin forever; dev builds abort with
+`ShadowTree.cpp: assertion failed (attempts < 1024)`.
+
+`ANDROID_SYNCHRONOUSLY_UPDATE_UI_PROPS` keeps Android out of that loop by applying transform,
+opacity, and color updates directly to views. Keep looping animations (`withRepeat`, shimmers,
+spinners) on those props. A layout prop such as `width` in the same animated style sends the
+whole update back through the shadow tree every frame, so pass static sizes as a plain style.