Ensure activitytracker updates get flushed to disk

src/main.cpp

@@ -28,6 +28,7 @@
 #include "KOReaderCredentialStore.h"
 #include "MappedInputManager.h"
 #include "OpdsServerStore.h"
+#include "ReadingSessionTracker.h"
 #include "ReadingStats.h"
 #include "RecentBooksStore.h"
 #include "SdCardFontSystem.h"
@@ -154,6 +155,9 @@ static bool deepSleepInProgress = false;
 
 void silentRestart() {
   if (deepSleepInProgress) return;  // sleeping supersedes the heap-defrag reboot
+  // ESP.restart() bypasses activity onExit(), so flush any in-flight reading
+  // session manually — otherwise a heap-defrag reboot mid-read loses the session.
+  globalReadingSessionTracker().end();
   silentRebootTarget = SILENT_REBOOT_TARGET_HOME;
   silentRebootMagic = SILENT_REBOOT_MAGIC;
   LOG_DBG("MAIN", "Silent restart (target=home)");
@@ -163,6 +167,7 @@ void silentRestart() {
 
 void silentRestartToReader() {
   if (deepSleepInProgress) return;  // sleeping supersedes the heap-defrag reboot
+  globalReadingSessionTracker().end();
   silentRebootTarget = SILENT_REBOOT_TARGET_READER;
   silentRebootMagic = SILENT_REBOOT_MAGIC;
   LOG_DBG("MAIN", "Silent restart (target=reader)");