Add scrolling, countdown, stopwatch, images, seconds, multiplier and degree sign

- Text elements can scroll in a window at a set speed; clock, countdown and
  stopwatch can show seconds. Moving pages are sent as instant frames (new
  Nano command D1) and paced by the estimated flip time.
- Countdown to a date and time (smart, days, days + time, with seconds),
  stopwatch (web UI, HA switch and reset button), image element (fixed or
  by Home Assistant state), multiplier for HA values, degree sign (char 127)
  in all fonts and the font converter.
- Page format version 2; version 1 pages are converted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/esp32/app.h

@@ -40,6 +40,15 @@ const char *appDeletePage(const char *name);
 const char *appSaveFont(const char *name, const uint8_t *data, size_t size);
 const char *appDeleteFont(const char *name);
 
+// The stopwatch of the dynamic pages (web UI and Home Assistant); redraws the display
+enum class StopwatchAction
+{
+	Start,
+	Stop,
+	Reset,
+};
+void appStopwatch(StopwatchAction action);
+
 // Live mode of the web UI
 void appShowLive(const uint8_t *bitmap);
 void appStopLive();