refactor(update-backend): streamline .env file handling process

- Replaced the previous method of copying .env files with a direct installation from a specified source path.
- Improved permissions and ownership settings for the .env file to enhance security.
- Added user feedback for successful file transfer and verification steps.

update-backend.sh

@@ -25,27 +25,21 @@ echo "Installing dependencies..."
 npm ci --production
 
 echo "Übernehme .env-Dateien vom Live-System..."
-if sudo -n test -f "$CURRENT_BACKEND/.env"; then
-    sudo -n cp "$CURRENT_BACKEND/.env" "$BACKEND_DIR/.env"
-    sudo -n chown tsschulz:tsschulz "$BACKEND_DIR/.env"
-    echo "✓ .env-Datei übernommen"
-else
-    echo "⚠ Keine lesbare .env-Datei in $CURRENT_BACKEND gefunden"
-fi
 
-TEMP_ENV_DIR="/tmp/yourpart-env-backup-$$"
-mkdir -p "$TEMP_ENV_DIR"
+SOURCE_ENV="/opt/yourpart/backend/.env"
+TARGET_ENV="$BACKEND_DIR/.env"
 
-echo "Sichere .env-Dateien aus $CURRENT_BACKEND..."
-if [ -d "$CURRENT_BACKEND" ]; then
-    find "$CURRENT_BACKEND" -maxdepth 1 -name '.env*' -type f -exec cp {} "$TEMP_ENV_DIR/" \; 2>/dev/null || true
-    if [ "$(ls -A "$TEMP_ENV_DIR" 2>/dev/null)" ]; then
-        echo "✓ .env-Dateien gesichert: $(ls "$TEMP_ENV_DIR")"
-        cp "$TEMP_ENV_DIR"/.env* "$BACKEND_DIR"/ 2>/dev/null || true
-    else
-        echo "⚠ Keine .env-Dateien in $CURRENT_BACKEND gefunden"
-    fi
-fi
+echo "Quelle: $SOURCE_ENV"
+echo "Ziel:   $TARGET_ENV"
+
+sudo -n ls -l "$SOURCE_ENV"
+sudo -n install -m 600 -o yourpart -g yourpart "$SOURCE_ENV" "$TARGET_ENV"
+
+echo "Prüfe kopierte Datei..."
+ls -l "$TARGET_ENV"
+sudo -n head -n 1 "$TARGET_ENV" >/dev/null
+
+echo "✓ .env-Datei wurde übernommen"
 
 sudo -n mkdir -p "$DATA_DIR/adult-verification"
 
@@ -61,10 +55,6 @@ sudo -n chmod -R 755 "$BACKEND_DIR"
 sudo -n chown -R yourpart:yourpart "$DATA_DIR"
 sudo -n chmod -R 755 "$DATA_DIR"
 
-if [ -f "$BACKEND_DIR/.env" ]; then
-    sudo -n chmod 600 "$BACKEND_DIR/.env"
-fi
-
 echo "Updating systemd service..."
 sudo -n cp "$TARGET_DIR/yourpart.service" /etc/systemd/system/
 sudo -n systemctl daemon-reload