feat(core polyfills): Add polyfill for navigation API.

This polyfill adds support for the "navigate" event on the navigation
object. We path "history.pushState" and "history.replaceState" to send
the "navigate" event on the "window.navigation" object when the URL
changes.

This polyfill is for current Firefox and Safari. Chrome based browsers
already support this.

More information on:
https://developer.mozilla.org/en-US/docs/Web/API/Navigation/navigate_event

src/core/polyfills.js

@@ -33,3 +33,30 @@
         true
     );
 })();
+
+// Navigation polyfill for Firefox and Safari, as of 2024-01-04
+// NOTE: this is a very basic polyfill, it only supports firing a `navigate`
+// event on location change and even that without interception support, etc.
+!(function () {
+    if (window.navigation == undefined) {
+        // Create a navigation object on the window
+        // We create a DOM element for the navigation object so that we can
+        // attach events on it.
+        window.navigation = document.createElement("div");
+
+        // Patch pushState to trigger an `navigate` event on the navigation
+        // object when the URL changes.
+        const pushState = window.history.pushState;
+        window.history.pushState = function () {
+            pushState.apply(window.history, arguments);
+            window.navigation.dispatchEvent(new Event("navigate"));
+        };
+
+        // Same with replaceState
+        const replaceState = window.history.replaceState;
+        window.history.replaceState = function () {
+            replaceState.apply(window.history, arguments);
+            window.navigation.dispatchEvent(new Event("navigate"));
+        };
+    }
+})();