screen-lock: the operator's lock screen is kept, i3lock-color with its blur, ring and clock

The first version swapped the colour build for the distribution's plain i3lock and locked to black;
adopting means keeping what the operator had. Plain i3lock remains the fallback, with a blurred
screenshot of its own.

modules/screen-lock/README.md

@@ -71,3 +71,13 @@ locker's options change with it.
 - `node-lock-screen`, `x11-display` and the `xinitrc` slot are ADR 0208's. Until the controller knows
   them, `mctl` reads them as unknown.
 - `xset` comes with the display server's module (`xorg`).
+
+## The operator's look is kept (changed 2026-10-04)
+
+The first version replaced the colour build with the distribution's plain i3lock, which locked to a
+black screen. It is reverted: the lock looks as it did before the mesh, with the screen blurred, an
+orange ring, the time and the date. That is i3lock-color, which comes from the distribution's user
+repository, so it is kept as found and no longer declared absent. The package and how such software
+reaches a machine are research 027's first question. The locker checks which build it has. On a
+machine with only the plain i3lock, it shows a blurred screenshot it takes itself, with the plain
+ring.