Fail if render screen never activates

build/client-renderer/src/client/java/dev/github/copilot/renameable/RenderCatalogClient.java

@@ -28,6 +28,7 @@ import net.minecraft.world.item.ItemStack;
 
 public final class RenderCatalogClient implements ClientModInitializer {
     private static final Gson GSON = new Gson();
+    private static final long SCREEN_ACTIVATION_TIMEOUT_MILLIS = 30_000L;
     private static final long CAPTURE_TIMEOUT_MILLIS = 120_000L;
 
     private final List<RenderJob> jobs = new ArrayList<>();
@@ -62,6 +63,22 @@ public final class RenderCatalogClient implements ClientModInitializer {
             System.out.println("[renderer] opening render screen");
             client.setScreenAndShow(renderScreen);
         });
+
+        Thread activationWatchdog = new Thread(() -> {
+            try {
+                Thread.sleep(SCREEN_ACTIVATION_TIMEOUT_MILLIS);
+            } catch (InterruptedException exception) {
+                Thread.currentThread().interrupt();
+                return;
+            }
+
+            if (!renderScreen.activated) {
+                System.err.println("[renderer] render screen never activated within " + SCREEN_ACTIVATION_TIMEOUT_MILLIS + "ms");
+                Runtime.getRuntime().halt(1);
+            }
+        }, "renderer-activation-watchdog");
+        activationWatchdog.setDaemon(true);
+        activationWatchdog.start();
     }
 
     private void loadJobs(Path manifestPath) throws IOException {
@@ -222,7 +239,7 @@ public final class RenderCatalogClient implements ClientModInitializer {
     private final class RenderScreen extends Screen {
         private boolean captureQueued;
         private long captureQueuedAtMillis;
-        private boolean activated;
+        private volatile boolean activated;
 
         private RenderScreen() {
             super(Component.literal("Rendering renameable items"));