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/logic/page_render.cpp

@@ -0,0 +1,58 @@
+#include "logic/page_render.h"
+
+#include <string.h>
+
+#include "logic/bitmap_format.h"
+#include "logic/builtin_fonts.h"
+
+static Font usableFont(PageResources &resources, const char *name)
+{
+	Font font = resources.font(name);
+	if (validFont(font.data, font.size) && font.scale >= 1)
+		return font;
+	return builtinFont(*findBuiltinFont(FONT_NORMAL_NAME));
+}
+
+static void clearBox(uint8_t *bitmap, int x, int y, int width, int height)
+{
+	for (int yy = y; yy < y + height; yy++)
+		for (int xx = x; xx < x + width; xx++)
+			setBitmapPixel(bitmap, xx, yy, false);
+}
+
+void renderPage(const DynamicPage &page, const LocalTime &time, PageResources &resources, uint8_t *bitmap,
+				ElementBox *boxes)
+{
+	memset(bitmap, 0, BITMAP_BYTES);
+	const PageSlot *slot = activeSlot(page, time.hour * 60 + time.minute);
+	if (slot && slot->bitmap[0] && !resources.background(slot->bitmap, bitmap))
+		memset(bitmap, 0, BITMAP_BYTES);
+
+	for (int i = 0; i < page.element_count && i < PAGE_ELEMENTS; i++)
+	{
+		const PageElement &e = page.elements[i];
+		const char *ha_value = e.type == ElementType::HaValue ? resources.haValue(e) : nullptr;
+		char text[64];
+		elementText(e, time, ha_value, text, sizeof(text));
+
+		Font font = usableFont(resources, e.font);
+		int width = textWidth(font, text), height = fontHeight(font);
+		int x = e.x;
+		if (e.align == Align::Center)
+			x -= width / 2;
+		else if (e.align == Align::Right)
+			x -= width;
+
+		if (e.overlay == Overlay::Box)
+			clearBox(bitmap, x - 1, e.y - 1, width + 2, height + 2);
+		drawText(bitmap, font, x, e.y, text, e.overlay == Overlay::Invert ? DrawMode::Invert : DrawMode::Set);
+
+		if (boxes)
+		{
+			boxes[i].x = x;
+			boxes[i].y = e.y;
+			boxes[i].width = width;
+			boxes[i].height = height;
+		}
+	}
+}