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/logic/builtin_pages.h

@@ -2,8 +2,8 @@
 
 #include "logic/page.h"
 
-// The built-in dynamic pages. They can't be changed or deleted; the web UI saves an edited
-// copy under a new name.
+// The original dynamic pages. display/page_store stores a copy of each at boot that can be
+// edited; the original is the fallback (deleting the copy resets the page).
 //
 //   Clock  Pikachu with the time in a thought bubble, yawning from 17:00 (the clock of
 //          the old firmware; also the default page)
@@ -12,5 +12,7 @@
 
 int builtinPageCount();
 const char *builtinPageName(int index);
+// The built-in name as it is written, nullptr when it is no built-in page
+const char *builtinPageName(const char *name);
 // False when there is no built-in page with this name (compared without case)
 bool builtinPage(const char *name, DynamicPage &page);