add shikane-watchdog user service to auto-recover shikane deadlocks

.config/sway/scripts/shikane-watchdog.sh

@@ -0,0 +1,49 @@
+#!/bin/sh
+# shikane-watchdog: auto-recover shikane from its deadlock bug.
+#
+# Bug (shikane 1.1.1): if a variant application is discarded mid-way
+# (e.g. by a failing DP atomic commit), the daemon gets stuck in
+# VariantInProgress/Discarded and keeps logging
+#   [WARN shikane::variant] Received invalid input AtomicChangeDone at state Discarded
+# `shikanectl reload` does not recover it; a service restart does
+# (re-applies the active profile in ~1s).
+#
+# A healthy daemon's last state-machine line is "VariantApplied".
+
+set -u
+
+unit=shikane
+stuck=0
+
+logs3=$(journalctl --user -u "$unit" -q --since "-3min" 2>/dev/null)
+[ -z "$logs3" ] && exit 0
+
+latest3=$(printf '%s\n' "$logs3" | grep 'daemon::state_machine' | tail -1)
+
+if [ -n "$latest3" ]; then
+    case "$latest3" in
+        *VariantApplied*)
+            : ;;  # healthy
+        *)
+            # InProgress/Discarded within the last 3 min: only a deadlock
+            # if the WARN signature is present (a legitimate slow transition
+            # has no WARN)
+            printf '%s\n' "$logs3" | grep -q 'invalid input' && stuck=1
+            ;;
+    esac
+else
+    # No state change in the last 3 min — check the last known state
+    last10=$(journalctl --user -u "$unit" -q --since "-10min" 2>/dev/null \
+        | grep 'daemon::state_machine' | tail -1)
+    case "$last10" in
+        '' | *VariantApplied*)
+            : ;;  # stable and applied, or nothing to check
+        *)
+            stuck=1 ;;  # stuck in-progress/discarded for >3 min
+    esac
+fi
+
+if [ "$stuck" -eq 1 ]; then
+    echo "shikane-watchdog: shikane stuck, restarting" >&2
+    systemctl --user restart "$unit"
+fi