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>

docs/web-ui.md

@@ -25,7 +25,8 @@ Bitmaps that pages or rules use are in their own subsection.
 Dynamic pages: a background per time of day, a bitmap or an [icon](#icons) (e.g. Pikachu
 from 00:00, yawning Pikachu from 17:00) with up to 8 elements on top. The preview is drawn by the ESP32, so it
 is exactly what the display shows; drag the elements on it, or select one and use the
-arrow keys. Built-in pages can be copied, not changed. See the [pictures of the pages](pages.md).
+arrow keys. The Clock page (Pikachu, the default) is a normal page that can be changed;
+its Reset button brings back the original. See the [pictures of the pages](pages.md).
 
 | Element | Options |
 |---------|---------|
@@ -57,7 +58,8 @@ Rules bring a page to the front from a Home Assistant state (an entity or attrib
 `is not`, `above`, `below`): they show it while the state is true, add it to the rotation
 while it is true, or show it for a while when it becomes true. Each rule is read at its own
 interval (2-600 s) and can be limited to some of the blocks. The first rule that shows a
-page wins. The display schedule ([Settings](#settings)) still decides when the display is on.
+page wins. A rule can leave a page chosen by hand alone (untick "also over a page chosen by
+hand"): it then waits until that pick ends (the next block or "Back to schedule"). The display schedule ([Settings](#settings)) still decides when the display is on.
 
 ![Schedule](../Pictures/web-ui/schedule.png)