fix(ci): set WORKSPACE_ID for the runtime-pin smoke import

platform_auth.py validates WORKSPACE_ID at module load — EC2 user-data
sets it from cloud-init, but the CI smoke-test was missing it and
failed with 'WORKSPACE_ID is empty'. Set a placeholder UUID so the
import gate exercises only the dep-resolution path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/runtime-pin-compat.yml

@@ -68,5 +68,10 @@ jobs:
           /tmp/venv/bin/pip show molecule-ai-workspace-runtime a2a-sdk \
             | grep -E '^(Name|Version):'
       - name: Smoke import — fail if metadata declares deps that don't satisfy real imports
+        # WORKSPACE_ID is validated at import time by platform_auth.py — EC2
+        # user-data sets it from the cloud-init template; set a placeholder
+        # here so the import smoke doesn't trip on the env-var guard.
+        env:
+          WORKSPACE_ID: 00000000-0000-0000-0000-000000000001
         run: |
           /tmp/venv/bin/python -c "from molecule_runtime.main import main_sync; print('runtime imports OK')"