feat: Release testing, cleaner resets and screenshots; skill updates

- vmwatch.sh --release: run the newest GitHub release in the VM.
- vmreset.sh: skip the broken krfoss mirror, install shellcheck.
- vmshot.sh --clean: close Steam, CachyOS Hello and Konsole first.
- Skill: items 1-7, menu loop and restart question, current inputs, finish on a fresh snapshot, release testing, Steamify shortcut, zsh pitfall.

scripts/vmshot.sh

@@ -1,15 +1,26 @@
 #!/bin/bash
 # Screenshot the guest's Plasma session to a file on the host.
-#   scripts/vmshot.sh <out.png>
+#   scripts/vmshot.sh [--clean] <out.png>
+#   --clean  first close what starts with the session and covers the desktop
+#            (Steam, CachyOS Hello) and the wizard's Konsole.
 # spectacle started straight from SSH crashes; run it as a user unit so it
 # gets the session's environment.
 # Env: VM_USER (theupriser), VM_PORT (2222), VM_HOST (localhost), GUEST_UID (1000).
 set -euo pipefail
 . "$(dirname "$0")/common.sh"
-out="${1:?usage: $0 <out.png>}"
-{ printf 'uid=%q\n' "${GUEST_UID:-1000}"; cat << 'REMOTE'
+clean=""
+[[ "${1:-}" == --clean ]] && { clean=1; shift; }
+out="${1:?usage: $0 [--clean] <out.png>}"
+{ printf 'uid=%q clean=%q\n' "${GUEST_UID:-1000}" "$clean"; cat << 'REMOTE'
 export XDG_RUNTIME_DIR=/run/user/$uid DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$uid/bus
 rm -f /tmp/vmshot.png
+if [ -n "$clean" ]; then
+    # Steam as a whole: closing only its web helper leaves a black window.
+    # It comes back at the next login (steam-desktop-autostart).
+    steam -shutdown >/dev/null 2>&1 & sleep 5; pkill -u "$USER" -x steam; pkill -u "$USER" -x steamwebhelper
+    pkill -u "$USER" cachyos-hello; pkill -u "$USER" -x konsole
+    sleep 2
+fi
 sleep 2
 systemd-run --user --wait -q spectacle -b -n -f -o /tmp/vmshot.png
 REMOTE