feat(P19): central pipeline contract + shell reproducibility + output streaming (v1.4.1)

---ci---
project: acdl
phase: 19
milestone: v1.4
status: execute
---

Add declarative pipeline contract (schemas/pipeline.schema.json +
pipelines/ci.yaml) as single source of truth for both Gitea Actions (dev)
and GitHub Actions (production) workflows. Both workflow files are
byte-identical and validated against the contract by 32 new tests.

Add scripts/run_ci.sh for shell reproducibility — mirrors the CI pipeline
locally (lint → test → check-only), exits 0 with 'CI PIPELINE OK'.

Update scripts/run_platform.sh to stream output by default: terraform
init/validate/plan via tee, Checkov compliance results with per-record
severity/rule/pass-fail, and emitted Terraform in --check-only. New
--quiet flag for log-only mode.

Requirements: REQ-43 (central pipeline contract), REQ-44 (shell
reproducibility), REQ-45 (output streaming). 122 tests pass (90 + 32).

.github/workflows/ci.yml

@@ -1,3 +1,18 @@
+# ACDL CI Pipeline — Gitea Actions (dev environment)
+#
+# This workflow implements the central pipeline contract:
+#   pipelines/ci.yaml (validated against schemas/pipeline.schema.json)
+#
+# The same contract is implemented by .github/workflows/ci.yml (GitHub
+# Actions, production). Both files must be byte-identical — the only
+# declared difference is the forge/runtime, not the stages or commands.
+#
+# Shell reproducibility: scripts/run_ci.sh runs the same 3 stages locally.
+#
+# Stages (from the contract):
+#   1. lint       — py_compile all Python files
+#   2. test       — pytest test suite (offline, no AWS)
+#   3. check-only — run_platform.sh --check-only (offline, no AWS)
 name: acdl-ci
 
 on: