Install the Globus Compute SDK in the API image

api/Dockerfile

@@ -12,6 +12,9 @@ WORKDIR /app
 # Install Python deps
 COPY api/requirements.txt ./requirements.txt
 RUN pip install --no-cache-dir -r requirements.txt
+# The computation API calls the registered RCAC gateway (status checks and
+# artifact downloads). Same pin as the worker; pymatgen stays worker-only.
+RUN pip install --no-cache-dir globus-compute-sdk==3.16.1
 
 # Copy API source and fallback dataset
 COPY api/ ./