Grounds the AI assistant (0.5.0) in the account's own content so it can
answer instead of handing off.
- Hybrid retrieval: Postgres full-text search for every account; optional
semantic search (pgvector + OpenAI text-embedding-3-small) when an
embeddings key is set. Semantic-primary, topped up with FTS.
- src/lib/ai: chunk, embeddings, knowledge (ingest + retrieve), query;
buildSystemPrompt gains a knowledge block; config carries an
(optional) embeddings key.
- Wired into /api/ai/draft and the auto-reply bot (best-effort — never
blocks a reply).
- KB API (/api/ai/knowledge CRUD + /reindex) and a Settings → AI
Assistant knowledge-base manager + embeddings-key field.
- Migration 030: pgvector, ai_knowledge_documents, ai_knowledge_chunks
(fts + embedding), match RPCs, ai_configs.embeddings_api_key.
Migration required: supabase/migrations/030_ai_knowledge.sql.
Stacked on feat/ai-reply-assistant (#329).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
