feat: add PaddleOCR-vl loader support and implement retrieval router infrastructure (#23945)

Co-authored-by: Tim Baek <tim@openwebui.com>
Co-authored-by: joaoback <156559121+joaoback@users.noreply.github.com>

backend/open_webui/retrieval/loaders/main.py

@@ -23,7 +23,7 @@ from open_webui.retrieval.loaders.external_document import ExternalDocumentLoade
 from open_webui.retrieval.loaders.mistral import MistralLoader
 from open_webui.retrieval.loaders.datalab_marker import DatalabMarkerLoader
 from open_webui.retrieval.loaders.mineru import MinerULoader
-
+from open_webui.retrieval.loaders.paddleocr_vl import PaddleOCRVLLoader
 
 from open_webui.env import GLOBAL_LOG_LEVEL, REQUESTS_VERIFY
 
@@ -399,6 +399,15 @@ class Loader:
                 api_key=self.kwargs.get('MISTRAL_OCR_API_KEY'),
                 file_path=file_path,
             )
+        elif (
+            self.engine == 'paddleocr_vl'
+            and self.kwargs.get('PADDLEOCR_VL_TOKEN') != ''
+        ):
+            loader = PaddleOCRVLLoader(
+                api_url=self.kwargs.get('PADDLEOCR_VL_BASE_URL'),
+                token=self.kwargs.get('PADDLEOCR_VL_TOKEN'),
+                file_path=file_path,
+            )
         else:
             if file_ext == 'pdf':
                 loader = PyPDFLoader(