First task of Phase 3b-i (notion semantic search). Adds _search_llm.py that dispatches to the anthropic SDK when ANTHROPIC_API_KEY is set, falls back to `claude -p` CLI otherwise, and raises a clear setup error if neither works. Symlinks _notion_compat.py from 32-notion-writer so both skills share one source of truth. 3 tests cover the three dispatch paths. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>