Fix: onPageStarted url param is String? in GV 147

app/src/main/java/dev/nova/browser/TabManager.kt

@@ -106,7 +106,8 @@ class TabManager(private val runtime: GeckoRuntime, private val context: Context
             }
         }
         session.progressDelegate = object : GeckoSession.ProgressDelegate {
-            override fun onPageStarted(session: GeckoSession, url: String) {
+            // GV 147 signature: url is nullable here.
+            override fun onPageStarted(session: GeckoSession, url: String?) {
                 loadingStates[tabId] = true
                 progressStates[tabId] = 0
             }
@@ -197,9 +198,7 @@ class TabManager(private val runtime: GeckoRuntime, private val context: Context
 
     private fun persistHistory() {
         try {
-            val arr = JSONArray()
-            history.forEach { arr.put(it) }
-            File(context.filesDir, "history.json").writeText(arr.toString())
+            historyFile.writeText(JSONArray().apply { history.forEach { put(it) } }.toString())
         } catch (e: Exception) {
             Log.w("Nova", "persistHistory failed", e)
         }
@@ -207,9 +206,8 @@ class TabManager(private val runtime: GeckoRuntime, private val context: Context
 
     private fun loadHistory() {
         try {
-            val f = File(context.filesDir, "history.json")
-            if (!f.exists()) return
-            val arr = JSONArray(f.readText())
+            if (!historyFile.exists()) return
+            val arr = JSONArray(historyFile.readText())
             history.clear()
             for (i in 0 until arr.length()) {
                 val url = arr.optString(i)