Add dynamic pages with clock, date, Home Assistant values and fonts

The hardcoded clock is now the built-in dynamic page "Clock". A dynamic page
has a background bitmap per time of day and up to 8 elements (clock, date,
Home Assistant value, text), each with position, alignment, font and overlay.
Pages are drawn on the ESP32, also for the web previews.

- Pages tab in the web UI: page editor with drag and drop, font upload
  (TTF/OTF converted in the browser to the FDF1 dot font format)
- Built-in fonts Small, Normal, Large and Full height (generated by
  tools/make_builtin_fonts.py), built-in bitmaps Pikachu and Pikachu yawning
- Home Assistant values over the REST API (URL and token in the HA tab)
- Settings version 4: evening settings removed (now time slots of the Clock
  page), old records are converted
- HA Mode dropdown lists the dynamic pages and bitmaps

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

src/esp32/display/page_resources.cpp

@@ -0,0 +1,22 @@
+#include "display/page_resources.h"
+
+#include "display/bitmap_store.h"
+#include "display/font_store.h"
+#include "net/ha_api.h"
+
+StoredPageResources pageResources;
+
+bool StoredPageResources::background(const char *name, uint8_t *bitmap)
+{
+	return loadBitmap(name, bitmap);
+}
+
+Font StoredPageResources::font(const char *name)
+{
+	return findFont(name);
+}
+
+const char *StoredPageResources::haValue(const PageElement &element)
+{
+	return haApiValue(element.entity, element.attribute);
+}