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.
Implement discover_kaizen_scheduled_repos and discover_kaizen_projects per
kaizen-agentic ADR-005 contract: State Hub roster, roster.yaml filter, schedule
validation, and prepare_command emission. Register kaizen/resolver/shell source
types with unit tests and runbook dry-run instructions.