feat: Add BE changes for captain pdf support for faq generation (#12113)

lib/custom_exceptions/pdf_processing_error.rb

@@ -0,0 +1,25 @@
+module CustomExceptions
+  class PdfProcessingError < Base
+    def initialize(message = 'PDF processing failed')
+      super(message)
+    end
+  end
+
+  class PdfUploadError < PdfProcessingError
+    def initialize(message = 'PDF upload failed')
+      super(message)
+    end
+  end
+
+  class PdfValidationError < PdfProcessingError
+    def initialize(message = 'PDF validation failed')
+      super(message)
+    end
+  end
+
+  class PdfFaqGenerationError < PdfProcessingError
+    def initialize(message = 'PDF FAQ generation failed')
+      super(message)
+    end
+  end
+end