feat: add local test runner script

Creates a temporary venv, installs shiv, builds the laconic-so package,
and runs any test script in isolation. Cleans up on exit.

Usage: ./tests/scripts/run-test-local.sh tests/webapp-test/run-webapp-test.sh

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/scripts/run-test-local.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+# Run a test suite locally in an isolated venv.
+#
+# Usage:
+#   ./tests/scripts/run-test-local.sh <test-script>
+#
+# Examples:
+#   ./tests/scripts/run-test-local.sh tests/webapp-test/run-webapp-test.sh
+#   ./tests/scripts/run-test-local.sh tests/smoke-test/run-smoke-test.sh
+#   ./tests/scripts/run-test-local.sh tests/k8s-deploy/run-deploy-test.sh
+#
+# The script creates a temporary venv, installs shiv, builds the laconic-so
+# package, runs the requested test, then cleans up.
+
+set -euo pipefail
+
+if [ $# -lt 1 ]; then
+  echo "Usage: $0 <test-script> [args...]"
+  exit 1
+fi
+
+TEST_SCRIPT="$1"
+shift
+
+if [ ! -f "$TEST_SCRIPT" ]; then
+  echo "Error: $TEST_SCRIPT not found"
+  exit 1
+fi
+
+REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+VENV_DIR=$(mktemp -d /tmp/so-test-XXXXXX)
+
+cleanup() {
+  echo "Cleaning up venv: $VENV_DIR"
+  rm -rf "$VENV_DIR"
+}
+trap cleanup EXIT
+
+cd "$REPO_DIR"
+
+echo "==> Creating venv in $VENV_DIR"
+python3 -m venv "$VENV_DIR"
+source "$VENV_DIR/bin/activate"
+
+echo "==> Installing shiv"
+pip install -q shiv
+
+echo "==> Building laconic-so package"
+./scripts/create_build_tag_file.sh
+./scripts/build_shiv_package.sh
+
+echo "==> Running: $TEST_SCRIPT $*"
+exec "./$TEST_SCRIPT" "$@"