Sync the shared issue-core ingestion key from OpenBao into
actcore-runtime-secret via External Secrets, with an interim coulombcore
ClusterSecretStore bootstrap script and deploy docs. Removes manual key
injection from bootstrap-secrets.sh.
Close the intent-gap workplan by documenting the weekly-sbom-staleness
promotion path, adding a null-sink and live REST smoke script, and recording
rollback steps for Railiance. Update SCOPE and deployment docs to reflect
ISSUE_SINK_TYPE=rest and the remaining actcore-runtime-secret key patch.
Issue-core requires a shared ingestion key on POST /issues/. The REST sink
now sends Authorization: Bearer using ISSUE_CORE_API_KEY and fails fast
when the key is missing under ISSUE_SINK_TYPE=rest.
Updates .env.example, emission boundary docs, and unit tests for the
header contract and missing-key error.
