packaging: split vgpu perception into separate libvgpu-perception0 + -dev packages

- the vmsig package no longer ships the gpu lib; it is a Sensor lib for the control, not the daemon
- vgpu-perception gets SOVERSION; runtime (libvgpu-perception0) and dev (-dev) packages, like the vmie split
- per-component install + a 3-package make deb; fix a stale comment (the windows producer is in-tree)

packaging/deb/vgpu-dev/control.in

@@ -0,0 +1,10 @@
+Package: libvgpu-perception-dev
+Version: @VERSION@
+Section: libdevel
+Priority: optional
+Architecture: amd64
+Depends: @DEPENDS@
+Maintainer: @MAINTAINER@
+Description: Host-side vgpu perception library (development files)
+ Headers (vgpu_perception.h, vgpu_stream.h) and the linker namelink for
+ libvgpu-perception. Install this to build a control/shell against the perception API.

packaging/deb/vgpu0/control.in

@@ -0,0 +1,12 @@
+Package: libvgpu-perception0
+Version: @VERSION@
+Section: libs
+Priority: optional
+Architecture: amd64
+Depends: @DEPENDS@
+Maintainer: @MAINTAINER@
+Description: Host-side vgpu perception library
+ Reads the in-guest vgpu shared region (frames, cursor, geometry) from the host over a
+ read-only guest-RAM handle and exposes a perception API. A Sensor-layer library consumed
+ by a control/shell, independent of the signaling daemon. This package ships the runtime
+ shared object (libvgpu-perception.so.0).

packaging/deb/vgpu0/postinst

@@ -0,0 +1,10 @@
+#!/bin/sh
+set -e
+case "$1" in
+configure)
+    ldconfig || true
+    ;;
+abort-upgrade|abort-remove|abort-deconfigure)
+    ;;
+esac
+exit 0

packaging/deb/vmsig/control.in

@@ -5,9 +5,9 @@ Priority: optional
 Architecture: amd64
 Depends: @DEPENDS@
 Maintainer: @MAINTAINER@
-Description: VM signaling coherence daemon and host SI libraries
+Description: VM signaling coherence daemon
  vmsig serves a unix-socket control plane over the signaling layer for the VMs it
  discovers: lifecycle/state, coherent guest address-space context handoff, and arbitrated
- input and memory-write actuation. Ships the daemon (vmsigd), the signaling library, the
- host-side vgpu perception library, and a systemd unit. Configured via
- /etc/vmsig/vmsigd.conf.
+ input and memory-write actuation. Ships the daemon (vmsigd), the signaling library, and a
+ systemd unit. Configured via /etc/vmsig/vmsigd.conf. The host-side vgpu perception library
+ is a separate package (libvgpu-perception).