fix: restore wheels/ COPY without invalid shell operators

COPY does not support shell operators (||, 2>/dev/null).
Keep wheels/ for paddlepaddle whl installation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -24,7 +24,7 @@ WORKDIR /build
 
 # Copy dependencies
 COPY pyproject.toml ./
-COPY wheels/ ./wheels/ 2>/dev/null || true
+COPY wheels/ ./wheels/
 
 # Build venv
 RUN uv venv /build/venv --python python3.10 && \