fix: power_off works under systemd — absolute key path + freshly-woken retry

Two OFF-path bugs found during live testing:
- bscpylgtv's key store defaulted to a CWD-relative ./.aiopylgtv.sqlite;
  under systemd (cwd=/) it couldn't open the pairing key db. Pass an
  absolute key_file_path (LGTV_KEY_FILE override, else ~/.aiopylgtv.sqlite).
- A TV woken seconds earlier answers TCP :3000 but rejects WebSocket control
  for ~20-30s. Retry power_off (2 attempts, 10s apart); common case still
  succeeds first try in ~3s. Kept under the bridge's 60s subprocess timeout.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lgtv.sh

@@ -138,12 +138,23 @@ tv_off() {
         exit 1
     fi
     echo "TV at $ip — sending WebOS power_off..."
-    TV_IP="$ip" python3 - <<'PY'
+    # Retry a few times: a TV woken seconds ago answers TCP :3000 but isn't
+    # ready for a WebSocket control session for ~20-30s. The common case
+    # (TV already up) succeeds on the first try in ~3s.
+    local attempt
+    for attempt in 1 2; do
+        if TV_IP="$ip" python3 - <<'PY'
 import asyncio, os
 from bscpylgtv import WebOsClient
 
+# Pass the key store path explicitly. bscpylgtv otherwise defaults to a
+# CWD-relative ./.aiopylgtv.sqlite (and its $USER_HOME fallback isn't $HOME),
+# so under systemd (cwd=/) it can't find the TV's pairing key. Absolute path
+# = works regardless of cwd/env. Override with LGTV_KEY_FILE if needed.
+KEY = os.environ.get('LGTV_KEY_FILE') or os.path.expanduser('~/.aiopylgtv.sqlite')
+
 async def main():
-    client = await WebOsClient.create(os.environ['TV_IP'])
+    client = await WebOsClient.create(os.environ['TV_IP'], key_file_path=KEY)
     await client.connect()
     await client.power_off()
     await asyncio.sleep(1)
@@ -152,7 +163,15 @@ async def main():
 asyncio.run(main())
 print('power_off sent')
 PY
-    echo "Done."
+        then
+            echo "Done."
+            return 0
+        fi
+        echo "  power_off attempt $attempt failed (TV may still be waking); retrying..."
+        sleep 10
+    done
+    echo "ERROR: power_off failed after 2 attempts"
+    exit 1
 }
 
 tv_status() {