feat: Add NTP clock sync to Clock settings

Adds a "Sync Clock" action in Settings > Clock that connects to WiFi
(auto-connecting to saved networks or prompting for selection) and
performs a blocking NTP time sync. Shows the synced time on success
with an auto-dismiss countdown, or an error on failure.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/activities/settings/SettingsActivity.cpp

@@ -13,6 +13,7 @@
 #include "KOReaderSettingsActivity.h"
 #include "LanguageSelectActivity.h"
 #include "MappedInputManager.h"
+#include "NtpSyncActivity.h"
 #include "OtaUpdateActivity.h"
 #include "SetTimeActivity.h"
 #include "SetTimezoneOffsetActivity.h"
@@ -221,6 +222,9 @@ void SettingsActivity::toggleCurrentSetting() {
       case SettingAction::SetTimezoneOffset:
         enterSubActivity(new SetTimezoneOffsetActivity(renderer, mappedInput, onComplete));
         break;
+      case SettingAction::SyncClock:
+        enterSubActivity(new NtpSyncActivity(renderer, mappedInput, onComplete));
+        break;
       case SettingAction::None:
         // Do nothing
         break;
@@ -245,7 +249,8 @@ void SettingsActivity::rebuildClockActions() {
                                      [](const SettingInfo& s) { return s.type == SettingType::ACTION; }),
                       clockSettings.end());
 
-  // Always add Set Time
+  // Always add Sync Clock and Set Time
+  clockSettings.push_back(SettingInfo::Action(StrId::STR_SYNC_CLOCK, SettingAction::SyncClock));
   clockSettings.push_back(SettingInfo::Action(StrId::STR_SET_TIME, SettingAction::SetTime));
 
   // Only add Set UTC Offset when timezone is set to Custom