Implements three-phase AI assistant feature:
- Phase 0: RAG infrastructure with pgvector embeddings, Voyage AI integration,
tree chunking service, and semantic search over team's flow library
- Phase 1: In-session copilot panel during flow navigation with contextual
AI help, current step awareness, and suggested related flows
- Phase 2: Standalone AI chat page with persistent conversation history,
pin/delete, and configurable retention policies (account-level)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>