Make Ghostscript an optional dependency for tools that don't need it (#4840)

# Description of Changes
Make Ghostscript an optional dependency for tools that don't need it.

app/core/src/main/java/stirling/software/SPDF/Factories/ReplaceAndInvertColorFactory.java

@@ -5,6 +5,7 @@ import org.springframework.web.multipart.MultipartFile;
 
 import lombok.RequiredArgsConstructor;
 
+import stirling.software.SPDF.config.EndpointConfiguration;
 import stirling.software.common.model.api.misc.HighContrastColorCombination;
 import stirling.software.common.model.api.misc.ReplaceAndInvert;
 import stirling.software.common.util.TempFileManager;
@@ -18,6 +19,7 @@ import stirling.software.common.util.misc.ReplaceAndInvertColorStrategy;
 public class ReplaceAndInvertColorFactory {
 
     private final TempFileManager tempFileManager;
+    private final EndpointConfiguration endpointConfiguration;
 
     public ReplaceAndInvertColorStrategy replaceAndInvert(
             MultipartFile file,
@@ -26,6 +28,13 @@ public class ReplaceAndInvertColorFactory {
             String backGroundColor,
             String textColor) {
 
+        // Check Ghostscript availability for CMYK conversion
+        if (replaceAndInvertOption == ReplaceAndInvert.COLOR_SPACE_CONVERSION
+                && !endpointConfiguration.isGroupEnabled("Ghostscript")) {
+            throw new IllegalStateException(
+                    "CMYK color space conversion requires Ghostscript, which is not available on this system");
+        }
+
         return switch (replaceAndInvertOption) {
             case CUSTOM_COLOR, HIGH_CONTRAST_COLOR ->
                     new CustomColorReplaceStrategy(

app/core/src/main/java/stirling/software/SPDF/config/EndpointConfiguration.java

@@ -403,8 +403,6 @@ public class EndpointConfiguration {
         /* Ghostscript */
         addEndpointToGroup("Ghostscript", "repair");
         addEndpointToGroup("Ghostscript", "compress-pdf");
-        addEndpointToGroup("Ghostscript", "crop");
-        addEndpointToGroup("Ghostscript", "replace-invert-pdf");
 
         /* tesseract */
         addEndpointToGroup("tesseract", "ocr-pdf");

app/core/src/main/java/stirling/software/SPDF/controller/api/CropController.java

@@ -22,6 +22,7 @@ import io.swagger.v3.oas.annotations.Operation;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
+import stirling.software.SPDF.config.EndpointConfiguration;
 import stirling.software.SPDF.config.swagger.StandardPdfResponse;
 import stirling.software.SPDF.model.api.general.CropPdfForm;
 import stirling.software.common.annotations.AutoJobPostMapping;
@@ -37,6 +38,11 @@ import stirling.software.common.util.WebResponseUtils;
 public class CropController {
 
     private final CustomPDFDocumentFactory pdfDocumentFactory;
+    private final EndpointConfiguration endpointConfiguration;
+
+    private boolean isGhostscriptEnabled() {
+        return endpointConfiguration.isGroupEnabled("Ghostscript");
+    }
 
     @AutoJobPostMapping(value = "/crop", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
     @StandardPdfResponse
@@ -46,9 +52,13 @@ public class CropController {
                     "This operation takes an input PDF file and crops it according to the given"
                             + " coordinates. Input:PDF Output:PDF Type:SISO")
     public ResponseEntity<byte[]> cropPdf(@ModelAttribute CropPdfForm request) throws IOException {
-        if (request.isRemoveDataOutsideCrop()) {
+        if (request.isRemoveDataOutsideCrop() && isGhostscriptEnabled()) {
             return cropWithGhostscript(request);
         } else {
+            if (request.isRemoveDataOutsideCrop()) {
+                log.warn(
+                        "Ghostscript not available - 'removeDataOutsideCrop' option requires Ghostscript. Falling back to visual crop only.");
+            }
             return cropWithPDFBox(request);
         }
     }