v0.15.1

Changes

• Add LLM-powered commands: audit-openapi, review-published, propose-overlays, audit-guardrails
• Agent DSL definitions (tasks, handoff types, artifacts)
• Switch LLM commands from --dry-run to --show-prompt (auto-injected by cli-contracts)
• Adopt handler return-string pattern for show-prompt
• Track src/generated/ files for CI build