feat: let a teacher ask the sanctuary to call a child's parent

The coordinator already existed on the control computer and its contract
is frozen, so this is the classroom half of a contract that was read from
its README and source rather than guessed: four fields out, the status
topic subscribed before anything is published, and every word the teacher
reads taken from the coordinator's own message field.

It is a separate process, not a Plasma applet. A broker library, a
network timeout and a text entry have no business inside the only way a
teacher has of getting anywhere; if this dies the bar is untouched.

The panel mark is Breeze's call-outgoing. The old one was a bell, sitting
two inches from Plasma's notification bell in the same bar and meaning
something entirely different.

Two things it will not do: claim a call was displayed, and let a teacher
type the room. The machine already knows which room it is.

Sixty tests cover the contract without a broker. The live path was proven
against the real coordinator running in the lab, on a loopback broker,
with ProPresenter mocked and the church's networks rejected from inside
the container first.

Co-Authored-By: Claude Opus 5 <[email protected]>

config/plasma/xdg/kwinrulesrc

@@ -1,6 +1,6 @@
 # Window rules.
 #
-# There is one, and it is about video.
+# There are two: one about video, one about the Parent Call card.
 #
 # Everything else the classroom used to arrange by hand is ordinary window
 # manager behaviour and needs no rule: a dialog stays in front of the window
@@ -17,8 +17,8 @@
 # 314-line window arbiter was doing.
 
 [General]
-count=1
-rules=classroom-video
+count=2
+rules=classroom-video,classroom-parent-call
 
 [classroom-video]
 Description=Video is an appliance screen, not a window
@@ -30,3 +30,21 @@ wmclassmatch=3
 wmclasscomplete=false
 noborder=true
 noborderrule=2
+
+[classroom-parent-call]
+Description=Parent Call is a quick action, not a window
+wmclass=classroom-parent-call
+wmclassmatch=1
+wmclasscomplete=false
+# It is not an application, so it does not belong in the row of them. The
+# button that opened it is already in the bar.
+skiptaskbar=true
+skiptaskbarrule=2
+skipswitcher=true
+skipswitcherrule=2
+skippager=true
+skippagerrule=2
+# In front of the lesson a teacher was reading when they pressed the
+# button, rather than behind it.
+above=true
+aboverule=2