Org pin moved from 2.253.1 (bundles vulnerable fast-uri 3.1.0, 2 high
GHSAs) to 2.257.0 (bundles patched 3.1.2). Removes the blanket
dependabot ignore per the new handbook pinning policy (exact pins kept
current by Dependabot; blanket ignores banned).
Stand up the Phase 0 CDK scaffold for the daily APM work-order
analysis pipeline: two-stack CDK app (pipeline + grafana), classifier
and slack-post Lambda packages, dashboards-as-code, the local
drop-folder uploader, and a classifier smoke-test placeholder.
Wire CI/CD to the org reusable workflows: ci.yaml -> ci-python-sam
(ruff + cdk synth) and deploy.yaml -> cd-cdk (OIDC, cdk deploy --all).
Pin aws-cdk-lib==2.253.1; Lambdas target Python 3.12 / arm64.
Rewrite .gitignore to the org Python-CDK standard so the source-of-
truth files (CLAUDE.md, docs/, .claude/agents) are tracked while build
artifacts (.venv, cdk.out, caches) stay ignored.
Domain logic, stack resources, and dashboards are stubbed and filled
in across Phases 1-5 (docs/BUILD.md). cdk synth is green for both
stacks; ruff check/format pass.
