feat: add an own lock screen with the bubble and your wallpaper

doc/face-unlock.1.scd

@@ -18,9 +18,8 @@ a printed one does not either.
 
 A bubble at the top of the screen shows what is going on: it drops down when
 the camera starts looking, the face in it looks around, and when it recognises
-somebody two green rings spin and land around a tick. On Plasma and GNOME it
-shows above the lock screen too. *Animation speed* makes all of it faster or
-slower.
+somebody two green rings spin and land around a tick. It shows above the lock
+screen too. *Animation speed* makes all of it faster or slower.
 
 Run without a command it shows an interactive menu. Everything it can be told
 is reachable from there; the settings files behind it do not need to be edited
@@ -60,6 +59,12 @@ It is a convenience, not a security upgrade. See *HOW SAFE IS THIS*.
 *status*
 	What is on, and when the last unlock was.
 
+*lock*
+	Lock the screen. On Hyprland, Niri and other compositors whose lock
+	screen is a program of its own, with face-unlock's own lock screen,
+	which shows the bubble (see *DESKTOPS*). Elsewhere with the desktop's
+	lock screen. Returns once the screen is locked.
+
 *-h*, *--help*
 	Show a summary of the commands.
 
@@ -196,8 +201,8 @@ does not start a scan with every key.
 
 When the face matches, the agent unlocks the session the way its lock screen
 wants it: through logind, as *loginctl unlock-session* does, on Plasma and
-GNOME, and with SIGUSR1 for hyprlock and swaylock. Any other lock screen
-opens itself, through PAM (see *DESKTOPS*).
+GNOME, by itself on its own lock screen, and with SIGUSR1 for hyprlock and
+swaylock. Any other lock screen opens itself, through PAM (see *DESKTOPS*).
 
 Unlocked through logind, Plasma's lock screen cuts off its own password prompt
 and counts that as a wrong password. After a face unlock the daemon resets the
@@ -212,7 +217,8 @@ is under *DESKTOPS*.
 
 # DESKTOPS
 
-All of them on Wayland. sudo and admin prompts work the same everywhere.
+All of them on Wayland. sudo and admin prompts work the same everywhere, and
+so does the bubble, above the lock screen too.
 
 *KDE Plasma 6*
 	The lock is seen through org.freedesktop.ScreenSaver and logind, and
@@ -240,6 +246,17 @@ All of them on Wayland. sudo and admin prompts work the same everywhere.
 	when somebody comes back, and opens them with SIGUSR1. Those lock
 	screens cover the bubble, which shows the tick once they are gone.
 
+	For the bubble on the lock screen there is face-unlock's own: *lock*.
+	It shows the time, a password field (PAM service _face-unlock-lock_
+	when an administrator wrote one, else the distribution's password-auth,
+	common-auth or login) and the bubble, and a face opens it straight
+	away. Behind it is the picture on the desktop, as swaybg, awww (swww),
+	hyprpaper or wpaperd show it. *Wallpaper* under *Settings* puts another
+	picture there, one at random from a folder, or _none_; *Blur the
+	wallpaper* blurs it. If the agent dies while this screen is locked, the
+	compositor keeps it locked, and the agent takes the lock back when it
+	starts again.
+
 	Hyprland only starts the agent's user service under uwsm. Without it,
 	*enable* and *status* show what to add to its config.
 
@@ -310,7 +327,10 @@ _/run/face-unlock/socket_
 
 _$XDG_RUNTIME_DIR/face-unlock/agent.socket_
 	Where the daemon tells the agent about scans it did not start, for the
-	bubble.
+	bubble, and where *lock* asks it to lock.
+
+_$XDG_RUNTIME_DIR/face-unlock/locked_
+	There while face-unlock's own lock screen is up.
 
 _/usr/share/gnome-shell/extensions/face-unlock@loonixtools.github.io/_
 	The GNOME Shell extension that draws the bubble on GNOME.