fix: PPD backslash typo, >8-digit code guard, NickName, build validation

installer/build.sh

@@ -15,6 +15,14 @@ cp filter/kyofilter \
     installer/root/usr/libexec/cups/filter/
 chmod 755 installer/root/usr/libexec/cups/filter/kyofilter
 
+# Validate PPD (fail if it cannot be parsed at all)
+echo "Validating PPD..."
+cupstestppd installer/root/Library/Printers/PPDs/Contents/Resources/TA3505ci_AS.ppd 2>&1 \
+    | grep -v "WARN\|8-Bit\|Übersetzung\|sollte\|Präfix\|übliches\|Seite\|Abschnitt" \
+    | grep -v "FeedingEdgeConstraint\|kyofilter" \
+    | grep "FEHLER" && { echo "ERROR: PPD has unexpected errors" >&2; exit 1; } || true
+echo "PPD OK"
+
 # Build (unsigned if SIGN_IDENTITY not set)
 SIGN_ARGS=()
 if [ -n "${SIGN_IDENTITY}" ]; then