Add parallel uploading of documents

Signed-off-by: Daniel Henry <iamdanhenry@gmail.com>

README.md

@@ -5,7 +5,7 @@ FastAPI service that:
 - splits them into pages (JPEG)
 - OCRs each page via your llama.cpp OpenAI-compatible endpoint
 - converts each page back into a single-page PDF
-- uploads **one Paperless document per page**
+- uploads **one Paperless document per page** (all uploads run **in parallel**; OCR stays **one page at a time** for VRAM)
 - patches each uploaded document with:
   - `content` = OCR text
   - custom fields `notebook_id` (field id 1) and `notebook_page` (field id 2)
@@ -47,6 +47,9 @@ PAPERLESS_CUSTOM_FIELD_NOTEBOOK_ID=1
 PAPERLESS_CUSTOM_FIELD_NOTEBOOK_PAGE=2
 PAPERLESS_DOCUMENT_TYPE_ID=3
 
+# Optional: cap concurrent Paperless uploads (0 = unlimited)
+PAPERLESS_UPLOAD_CONCURRENCY=4
+
 # Rendering / OCR knobs
 RENDER_DPI=200
 OCR_MAX_TOKENS=1024