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/frames.h

@@ -3,15 +3,16 @@
 #include "BROSE9323.h"
 #include "logic/bitmap_format.h"
 #include "logic/display_controller.h"
+#include "logic/page_render.h"
 
 // Draws the screens on the flipdot display. Each method sends one complete frame.
 class FlipdotFrames : public Frames
 {
 public:
-	explicit FlipdotFrames(BROSE9323 &display);
+	FlipdotFrames(BROSE9323 &display, PageResources &resources);
 
-	// Pikachu with a thought bubble showing HH:MM (yawning in the evening)
-	void clock(int hour, int minute, bool evening) override;
+	// The page set with setDynamicPage(), drawn for this time
+	void dynamicPage(const LocalTime &time) override;
 	// "No WiFi" with the time below it
 	void noWifi(int hour, int minute) override;
 	// The bitmap set with setPageBitmap()
@@ -21,6 +22,7 @@ public:
 	// Blank, or the bitmap set with setOffBitmap()
 	void off() override;
 
+	void setDynamicPage(const DynamicPage &page);
 	void setPageBitmap(const uint8_t *bitmap);
 	void setLiveBitmap(const uint8_t *bitmap);
 	// nullptr: blank
@@ -28,6 +30,8 @@ public:
 
 private:
 	BROSE9323 &_display;
+	PageResources &_resources;
+	DynamicPage _dynamic;
 	uint8_t _page[BITMAP_BYTES] = {};
 	uint8_t _live[BITMAP_BYTES] = {};
 	uint8_t _off[BITMAP_BYTES] = {}; // all zero: blank