fix(test): pin real-PI DATA_DIR to runner-mounted data/dev

go test under internal/server previously preferred package-local
data/test, so materials never reached the pi-agent bind mount and
intake quality gates failed closed on empty sandboxes.

scripts/run-nightly-real-pi.sh

@@ -127,6 +127,10 @@ export RUNNER_AUTH_TOKEN="${TOKEN}"
 export PI_AGENT_MODEL="${MODEL_ID}"
 export RUN_PI_E2E=1
 export KB_REQUIRE_ONLINE="${KB_REQUIRE_ONLINE:-1}"
+# Host Go tests must write workspaces into the same tree the runner mounts
+# (docker-compose.dev.yml: ./data/dev/workspaces → /app/data/workspaces).
+export DATA_DIR="${DATA_DIR:-${ROOT}/data/dev}"
+echo "==> DATA_DIR=${DATA_DIR}"
 
 # Shared KB preflight (host :5432). Fail closed unless KB_ALLOW_OFFLINE=1.
 preflight_shared_kb() {