Kiosk: show all user-visible times as 12-hour AM/PM

Add datetime::formatHm12h/formatTime12h and use them for the Home footer
clock, the Timezone page's local-time sample, and the log viewer
timestamps. Storage and parsing remain 24-hour HH:MM. Extends the
date-format tests with the midnight/noon edge cases.

src/log_viewer_page.cpp

@@ -1,5 +1,6 @@
 #include "log_viewer_page.h"
 #include "app_state.h"
+#include "date_format.h"
 #include "timezone_helper.h"
 #include "logical_size.h"
 #include <SDL3/SDL.h>
@@ -256,7 +257,11 @@ void LogViewerPage::rebuildWrapped(float maxLineWidth) {
     using namespace radiantwave::logger;
 
     for (const auto& entry : rawEntries_) {
-        std::string timeStr = radiantwave::timezone::formatUtcToTimezone(entry.timestamp, currentTzCode_, "%Y-%m-%d %H:%M:%S");
+        std::string timeStr =
+            radiantwave::timezone::formatUtcToTimezone(entry.timestamp, currentTzCode_, "%Y-%m-%d") +
+            " " +
+            radiantwave::datetime::formatHm12h(
+                radiantwave::timezone::formatUtcToTimezone(entry.timestamp, currentTzCode_, "%H:%M"));
 
         std::string fullLineStr = "[" + timeStr + "] [" + std::string(logLevelToString(entry.level)) + "] [" + entry.component + "] " + entry.message;