Requirements, architecture, and epics now output as directories with
individual files per design point (_index.md + REQ-*.md/ADR-*.md/EPIC-*.md),
linked via relative paths for better referencing and downstream consumption.
Phase 6 handoff bridge simplified to read directly from individual EPIC files.
Phase 6 now creates brainstorm_artifacts-compatible bridge files
(.brainstorming/guidance-specification.md, feature-index.json, feature-specs)
when handing off to workflow:plan or req-plan, enabling context-search-agent
auto-discovery without modifying downstream consumers.
