Summary

• Replace the empty manifest artifact list with a representative bats-core tool artifact.
• Update the README and AI context contract maps to describe the artifact setup behavior.
• Make the walkthrough and validation suite guard that the artifact stays visible.

Validation

• bats tests/demo_test.bats
• ./tests/validate.sh
• git diff --check
• env GRADLE_USER_HOME=/private/tmp/base-demo-gradle-89 bats tests/java_services_test.bats
• env GRADLE_USER_HOME=/private/tmp/base-demo-gradle-89 bats tests/*.bats
• env BASE_HOME=/Users/rameshhp/work/base PYTHONPATH=/Users/rameshhp/work/base/cli/python:/Users/rameshhp/work/base/lib/python /Users/rameshhp/.base.d/base/.venv/bin/python -m base_setup --dry-run --manifest ./base_manifest.yaml --action setup base-demo

Fixes #93