fix: ensure pickling compatibility for OCROptions in multiprocessing

Co-authored-by: aider (openrouter/anthropic/claude-sonnet-4) <aider@aider.chat>

src/ocrmypdf/_jobcontext.py

@@ -38,10 +38,10 @@ class PdfContext:
         # Accept both types during transition
         if isinstance(options, Namespace):
             self.options = OCROptions.from_namespace(options)
-            self._legacy_options = options
+            self._namespace_options = options  # Keep original for PageContext
         else:
             self.options = options
-            self._legacy_options = None
+            self._namespace_options = options.to_namespace()  # Convert immediately for PageContext
         self.work_folder = work_folder
         self.origin = origin
         self.pdfinfo = pdfinfo
@@ -50,9 +50,7 @@ class PdfContext:
     @property
     def legacy_options(self) -> Namespace:
         """Provide Namespace for plugin compatibility."""
-        if self._legacy_options is None:
-            self._legacy_options = self.options.to_namespace()
-        return self._legacy_options
+        return self._namespace_options
 
     def get_path(self, name: str) -> Path:
         """Generate a ``Path`` for an intermediate file involved in processing.
@@ -91,11 +89,8 @@ class PageContext:
     def __init__(self, pdf_context: PdfContext, pageno):
         self.work_folder = pdf_context.work_folder
         self.origin = pdf_context.origin
-        # Always use the legacy options for PageContext to ensure pickling works
-        if hasattr(pdf_context.options, 'to_namespace'):
-            self.options = pdf_context.options.to_namespace()
-        else:
-            self.options = pdf_context.options
+        # Always use Namespace for PageContext to avoid pickling issues
+        self.options = pdf_context._namespace_options
         self.pageno = pageno
         self.pageinfo = pdf_context.pdfinfo[pageno]
         self.plugin_manager = pdf_context.plugin_manager
@@ -111,12 +106,7 @@ class PageContext:
     def __getstate__(self):
         state = self.__dict__.copy()
 
-        # Convert OCROptions to Namespace for pickling compatibility
-        if hasattr(state['options'], 'to_namespace'):
-            state['options'] = state['options'].to_namespace()
-        else:
-            state['options'] = copy(state['options'])
-        
+        state['options'] = copy(self.options)
         # Handle stream inputs
         if hasattr(state['options'], 'input_file'):
             if not isinstance(state['options'].input_file, str | bytes | os.PathLike):