fix: RAG service Dockerfile path patch (#767)

**Reason for Change**:
Docker file path fixed

**Requirements**

- [ ] added unit tests and e2e tests (if applicable).

**Issue Fixed**:
if we don't name the path as ragengine, it will report the following
error:

```
Traceback (most recent call last):
  File "/app/services/main.py", line 5, in <module>
    from vector_store_manager.manager import VectorStoreManager
  File "/app/services/vector_store_manager/manager.py", line 6, in <module>
    from ragengine.models import Document
ModuleNotFoundError: No module named 'ragengine'
```

**Notes for Reviewers**:

Signed-off-by: Bangqi Zhu <[email protected]>
Co-authored-by: Bangqi Zhu <[email protected]>

docker/ragengine/service/Dockerfile

@@ -3,16 +3,16 @@ FROM python:3.12-slim
 WORKDIR /app
 
 # Copy all files from ragengine/services into the app/services folder
-COPY presets/ragengine/ services/
+COPY presets/ragengine/ ragengine/
 
 # Set the PYTHONPATH environment variable
 ENV PYTHONPATH=/app
 
 # Install dependencies from requirements.txt
-RUN pip install --no-cache-dir -r services/requirements.txt
+RUN pip install --no-cache-dir -r ragengine/requirements.txt
 
 # Set the final working directory
-WORKDIR /app/services
+WORKDIR /app/ragengine
 
 # Run Using Following
 # docker build -f docker/ragengine/service/Dockerfile -t kaito-rag-service:0.0.1 .