Refactor: migrate pdf_parser.py to golang (#16323)

### What problem does this PR solve?

Http API based on onnx model.
pdf_parser.py to golang

### Type of change

- [x] Refactoring

docker/.env

@@ -25,7 +25,7 @@ DOC_ENGINE=${DOC_ENGINE:-elasticsearch}
 # - `gpu`
 DEVICE=${DEVICE:-cpu}
 
-COMPOSE_PROFILES=${DOC_ENGINE},${DEVICE}
+COMPOSE_PROFILES=${DOC_ENGINE},${DEVICE},deepdoc
 
 # The version of Elasticsearch.
 STACK_VERSION=${STACK_VERSION:-8.11.3}
@@ -308,3 +308,13 @@ THREAD_POOL_MAX_WORKERS=128
 
 #Option to disable login form for SSO
 DISABLE_PASSWORD_LOGIN=false
+
+# -----------------------------------------------------------------------------
+# DeepDoc OSS Vision Service
+# -----------------------------------------------------------------------------
+# URL for the deepdoc vision API (DLA, OCR, TSR) served by OSS ONNX models.
+# The `deepdoc` service defined in docker-compose.yml provides this endpoint.
+# When unset, the parser falls back to inline ONNX Runtime inference.
+DEEPDOC_URL=http://deepdoc:9390
+# Docker image for the OSS deepdoc service.  CPU-only; uses ONNX Runtime.
+DEEPDOC_IMAGE=deepdoc_oss:latest