[model-gateway] fix gateway docker build due to recent py code change (#13532)

docker/Dockerfile

@@ -316,7 +316,7 @@ RUN --mount=type=cache,target=/root/.cache/pip curl --proto '=https' --tlsv1.2 -
     && export PATH="/root/.cargo/bin:${PATH}" \
     && rustc --version && cargo --version \
     && python3 -m pip install maturin \
-    && cd /sgl-workspace/sglang/sgl-router \
+    && cd /sgl-workspace/sglang/sgl-router/bindings/python \
     && ulimit -n 65536 && maturin build --release --features vendored-openssl --out dist \
     && python3 -m pip install --force-reinstall dist/*.whl \
     && rm -rf /root/.cargo /root/.rustup target dist ~/.cargo \

docker/gateway.Dockerfile

@@ -57,7 +57,8 @@ WORKDIR /opt/sglang/sgl-router
 # install maturin and build the wheel with vendored OpenSSL
 RUN uv pip install maturin \
     && cargo clean \
-    && rm -rf dist/ \
+    && rm -rf bindings/python/dist/ \
+    && cd bindings/python \
     && maturin build --release --features vendored-openssl --out dist \
     && rm -rf /root/.cache
 
@@ -65,7 +66,7 @@ RUN uv pip install maturin \
 FROM base AS router-image
 
 # Copy the built package from the build image
-COPY --from=build-image /opt/sglang/sgl-router/dist/*.whl dist/
+COPY --from=build-image /opt/sglang/sgl-router/bindings/python/dist/*.whl dist/
 
 # Build the package and install
 RUN uv pip install --force-reinstall dist/*.whl