Add a web UI to the clock firmware

- Web UI on port 80: live view of the display, choose the page (clock or
  a bitmap), bitmaps (list, show, live, edit, delete), draw / image upload
  with conversion in the browser, live mode, settings, Home Assistant
- Live view from a shadow buffer in the BROSE9323 driver (shownPixel)
- Settings in NVS with the original behaviour as defaults: schedule times,
  quarter hours, yawning Pikachu, No WiFi screen, flip time, status LED,
  Home Assistant broker (restart on change)
- Bitmaps on LittleFS; new 320 KB partition, ota slots now 1.31 MB
- DisplayController: pages, live mode, settings; app.cpp holds the objects
- README for the recovery app; docs for the web UI
- Tests: settings, time parsing, bitmap format and names, schedule with
  settings, pages and live mode (95 total)

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

src/esp32/display/status_screen.cpp

@@ -5,10 +5,15 @@
 #include "config.h"
 #include "display/text.h"
 
-StatusScreen::StatusScreen(BROSE9323 &display, NanoLink &nano) : _display(display), _nano(nano)
+StatusScreen::StatusScreen(BROSE9323 &display, NanoLink &nano) : _display(display), _nano(nano), _flip_time(FLIP_TIME)
 {
 }
 
+void StatusScreen::setFlipTime(uint16_t flip_time)
+{
+	_flip_time = flip_time;
+}
+
 void StatusScreen::show(const char *line1, const char *line2, bool keep_on)
 {
 	Serial.printf("Display: %s / %s\n", line1, line2 ? line2 : "");
@@ -16,7 +21,7 @@ void StatusScreen::show(const char *line1, const char *line2, bool keep_on)
 	if (!_started)
 	{
 		_display.begin(&_nano.stream());
-		_display.setTiming(FLIP_TIME);
+		_display.setTiming(_flip_time);
 		_started = true;
 	}
 	drawTextLines(_display, line1, line2);