Rules can leave a manual pick alone, Clock is an editable page, fix HA attributes

- Rules: "also over a page chosen by hand" (on by default); off, a rule
  waits until the manual pick ends. Schedule store version 3, version 2
  records are read with the option on.
- The Clock page is stored at boot from the built-in one and can be
  edited; Reset (deleting it) brings back the original.
- Home Assistant attributes were never found: ArduinoJson 7.4 takes a
  char array key as a literal of its full array length.

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

src/esp32/app.cpp

@@ -335,11 +335,19 @@ const char *appSavePage(const char *name, const DynamicPage &page)
 
 const char *appDeletePage(const char *name)
 {
-	if (scheduleUses(page_schedule, name))
+	// A stored copy of a built-in page: deleting it resets the page, which stays
+	bool resets = builtinPageName(name) != nullptr;
+	if (!resets && scheduleUses(page_schedule, name))
 		return USED_BY_SCHEDULE;
 	const char *error = deletePage(name);
 	if (error)
 		return error;
+	if (resets)
+	{
+		if (sameName(shown, name))
+			reloadPage();
+		return nullptr;
+	}
 	if (sameName(settings.page, name))
 		setChosen(DEFAULT_PAGE);
 	return nullptr;