feat: improve Gotify variable extraction in backup script

- Enhanced the loading of Gotify variables from the .env file by adding checks for existing values.
- Ensured that only non-empty and non-comment lines are processed for GOTIFY_URL and GOTIFY_APP_TOKEN.

scripts/backup-restic.sh

@@ -9,12 +9,13 @@ if [ -f "$HOME/.restic-env" ]; then
     . "$HOME/.restic-env"
 fi
 
-# Load .env file if present (for Gotify variables)
-if [ -f ".env" ]; then
-    # shellcheck source=/dev/null
-    set -a
-    . ".env"
-    set +a
+# Extract Gotify variables from .env file if not set (ignore comments and empty lines)
+if [ -z "$GOTIFY_URL" ] && [ -f ".env" ]; then
+    GOTIFY_URL=$(grep -v '^#' .env | grep -v '^$' | grep '^GOTIFY_URL=' | head -1 | cut -d'=' -f2- | tr -d '"' | tr -d "'" | xargs || echo "")
+fi
+
+if [ -z "$GOTIFY_APP_TOKEN" ] && [ -f ".env" ]; then
+    GOTIFY_APP_TOKEN=$(grep -v '^#' .env | grep -v '^$' | grep '^GOTIFY_APP_TOKEN=' | head -1 | cut -d'=' -f2- | tr -d '"' | tr -d "'" | xargs || echo "")
 fi
 
 # Extract Gotify variables from docker-compose.yml if not set