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/net/home_assistant.cpp

@@ -12,6 +12,7 @@
 #include "config.h"
 #include "credentials.h"
 #include "display/bitmap_store.h"
+#include "display/page_store.h"
 #include "net/ha_page_select.h"
 #include "system/boot_target.h"
 
@@ -68,35 +69,51 @@ static void onPowerCommand(bool state, HASwitch *sender)
 	sender->setState(state);
 }
 
-// The bitmap names for the dropdowns: built-in ones first, then the uploaded ones
-// alphabetically. Rebuilt when bitmaps were added or deleted.
-static const std::vector<String> &bitmapNames()
+static bool lessName(const String &a, const String &b)
 {
-	static std::vector<String> names;
-	static bool loaded = false;
-	static uint32_t revision = 0;
-	if (loaded && revision == bitmapListRevision())
-		return names;
-	loaded = true;
-	revision = bitmapListRevision();
+	return strcasecmp(a.c_str(), b.c_str()) < 0;
+}
 
-	std::vector<String> uploaded;
-	names.clear();
+// The bitmap names for the dropdowns: built-in ones first, then the uploaded ones
+// alphabetically
+static std::vector<String> bitmapNames()
+{
+	std::vector<String> names, uploaded;
 	for (const BitmapInfo &b : listBitmaps())
 		(b.builtin ? names : uploaded).push_back(b.name);
-	std::sort(uploaded.begin(), uploaded.end(),
-			  [](const String &a, const String &b) { return strcasecmp(a.c_str(), b.c_str()) < 0; });
+	std::sort(uploaded.begin(), uploaded.end(), lessName);
 	names.insert(names.end(), uploaded.begin(), uploaded.end());
 	return names;
 }
 
-// A dropdown with one fixed option (the clock, or blank) followed by the bitmaps, for a
-// setting that holds either the fixed value or a bitmap name
-struct BitmapChoice
+// The dynamic pages the same way, followed by the bitmaps
+static std::vector<String> pageNames()
+{
+	std::vector<String> names, stored;
+	for (const PageInfo &p : listPages())
+		(p.builtin ? names : stored).push_back(p.name);
+	std::sort(stored.begin(), stored.end(), lessName);
+	names.insert(names.end(), stored.begin(), stored.end());
+	std::vector<String> bitmaps = bitmapNames();
+	names.insert(names.end(), bitmaps.begin(), bitmaps.end());
+	return names;
+}
+
+// Changes when bitmaps or pages were added or deleted
+static uint32_t listRevision()
+{
+	return bitmapListRevision() + pageListRevision();
+}
+
+// A dropdown for a setting that holds a name from the list, or optionally a fixed value
+// shown as an extra first option (the blank off image)
+struct NameChoice
 {
 	HAPageSelect &select;
-	const char *fixed_option; // shown in Home Assistant
+	const char *fixed_option; // shown in Home Assistant; nullptr: no fixed option
 	const char *fixed_value;  // stored in the settings
+	const char *fallback;     // shown when the setting's name is gone (what the display shows then)
+	std::vector<String> (*names)();
 	const char *(*setting)();
 	const char *(*choose)(const char *value); // returns nullptr or an error
 
@@ -106,28 +123,29 @@ struct BitmapChoice
 	char state_for[PAGE_NAME_SIZE]; // setting the state was published for
 	std::vector<String> options;
 
-	// The option for the setting; the fixed one when the bitmap is gone (the display
-	// falls back to the clock or blank then too)
 	const char *current()
 	{
 		const char *value = setting();
-		if (strcmp(value, fixed_value) != 0)
-			for (const String &option : options)
-				if (strcasecmp(option.c_str(), value) == 0)
-					return option.c_str();
-		return fixed_option;
+		if (fixed_option && strcmp(value, fixed_value) == 0)
+			return fixed_option;
+		for (const String &option : options)
+			if (strcasecmp(option.c_str(), value) == 0)
+				return option.c_str();
+		return fallback;
 	}
 
-	// Rebuilds the options when bitmaps were added or deleted and reports the setting
+	// Rebuilds the options when bitmaps or pages were added or deleted and reports the setting
 	void update()
 	{
-		if (!options_loaded || options_revision != bitmapListRevision())
+		if (!options_loaded || options_revision != listRevision())
 		{
-			const std::vector<String> &names = bitmapNames();
 			options_loaded = true;
-			options_revision = bitmapListRevision();
-			options.assign(1, fixed_option);
-			options.insert(options.end(), names.begin(), names.end());
+			options_revision = listRevision();
+			options.clear();
+			if (fixed_option)
+				options.push_back(fixed_option);
+			std::vector<String> list = names();
+			options.insert(options.end(), list.begin(), list.end());
 			select.setOptions(options);
 			state_known = false;
 		}
@@ -142,17 +160,19 @@ struct BitmapChoice
 
 	void command(const char *option)
 	{
-		const char *error = choose(strcmp(option, fixed_option) == 0 ? fixed_value : option);
+		const char *error = choose(fixed_option && strcmp(option, fixed_option) == 0 ? fixed_value : option);
 		if (error)
 			Serial.printf("Home Assistant \"%s\": %s\n", option, error);
 		update(); // report the (new) state back
 	}
 };
 
-// Bitmaps can't be called "clock", and the blank off image is stored as ""
-static BitmapChoice mode = {modeSelect, "Clock", PAGE_CLOCK, []() { return appSettings().page; }, appSelectPage};
-static BitmapChoice offImage = {offSelect, "Blank", OFF_PAGE_BLANK, []() { return appSettings().off_page; },
-								appSelectOffPage};
+// "Clock" is the built-in page (it was a fixed option before, so automations keep working)
+static NameChoice mode = {modeSelect, nullptr, nullptr, DEFAULT_PAGE, pageNames,
+						  []() { return appSettings().page; }, appSelectPage};
+// The blank off image is stored as ""
+static NameChoice offImage = {offSelect, "Blank", OFF_PAGE_BLANK, "Blank", bitmapNames,
+							  []() { return appSettings().off_page; }, appSelectOffPage};
 
 static void clearRemovedEntities()
 {