fixing no chunking error handling

src/ingestion/build_index.py

@@ -92,7 +92,10 @@ def build_index(source_dir: str, project_id: str):
     )
     
     print("Adding chunks to Chroma DB...")
-    vectorstore.add_documents(chunks)
+    if len(chunks) > 0:
+        vectorstore.add_documents(chunks)
+    else:
+        print("No readable text chunks found in this document.")
     
     save_manifest(manifest, manifest_path)
     print("Ingestion complete. Manifest updated.")