fix: force-remove staging container before deploy — handles both compose and docker-run containers

The deploy step used only 'docker compose down' which can't remove
containers created via 'docker run'. Now explicitly stops+removes
the named container first, then runs compose down as cleanup.

Permanent fix for the recurring CI deploy failure.

.github/workflows/deploy.yml

@@ -387,7 +387,10 @@ jobs:
 
       - name: Deploy staging
         run: |
-          # Stop old container and release memory
+          # Force-remove the staging container regardless of how it was created
+          # (compose-managed OR manually created via docker run)
+          docker stop corescope-staging-go 2>/dev/null || true
+          docker rm -f corescope-staging-go 2>/dev/null || true
           docker compose -f "$STAGING_COMPOSE_FILE" -p corescope-staging down --timeout 30 2>/dev/null || true
 
           # Wait for container to be fully gone and OS to reclaim memory (3GB limit)