Add new level transition state machine

src/game/analytics.c

@@ -9,9 +9,20 @@
 /* Initialize client_id in localStorage and store the analytics
  * API URL + key. Called once at startup. */
 EM_JS(void, js_analytics_init, (), {
-    /* Generate or retrieve a persistent client UUID */
+    /* Generate or retrieve a persistent client UUID.
+     * crypto.randomUUID() requires a secure context (HTTPS) and is
+     * absent in older browsers, so fall back to a manual v4 UUID. */
     if (!localStorage.getItem('jnr_client_id')) {
-        localStorage.setItem('jnr_client_id', crypto.randomUUID());
+        var uuid;
+        if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function') {
+            uuid = crypto.randomUUID();
+        } else {
+            uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
+                var r = Math.random() * 16 | 0;
+                return (c === 'x' ? r : (r & 0x3 | 0x8)).toString(16);
+            });
+        }
+        localStorage.setItem('jnr_client_id', uuid);
     }
     /* Store config on the Module for later use by other EM_JS calls.
      * ANALYTICS_URL and ANALYTICS_KEY are replaced at build time via