Fix CLI return code

Click does the work, and doesn't care about return values.
Also, we don't stop processing when one document fails, so we
can see all problems not just one.
So we need to error out if any of the documents failed.

Author: dannyadair

src/pdfbaker/__main__.py

@@ -56,12 +56,12 @@ def bake(
             keep_build=keep_build,
         )
         baker = PDFBaker(config_file, options=options)
-        baker.bake()
-        return 0
+        success = baker.bake()
+        sys.exit(0 if success else 1)
     except PDFBakerError as exc:
         logger.error(str(exc))
-        return 1
+        sys.exit(1)
 
 
 if __name__ == "__main__":
-    sys.exit(cli())
+    cli()

src/pdfbaker/baker.py

@@ -110,7 +110,11 @@ def __init__(
         )
 
     def bake(self) -> None:
-        """Create PDFs for all documents."""
+        """Create PDFs for all documents.
+
+        Returns:
+        bool: True if all documents were processed successfully, False if any failed
+        """
         pdfs_created: list[Path] = []
         failed_docs: list[tuple[str, str]] = []
 
@@ -156,6 +160,8 @@ def bake(self) -> None:
         if not self.keep_build:
             self.teardown()
 
+        return not failed_docs
+
     def teardown(self) -> None:
         """Clean up (top-level) build directory after processing."""
         self.log_debug_subsection(