- New app/services/embeddings.py: TURNSTONE_EMBED_* env vars, multi-backend support
- embedder.py delegates to service layer; re-exports EMBEDDING_AVAILABLE for compat
- retriever.py updated to use service layer
- Test coverage updated in tests/context/test_embedder.py
- Add context_block param to summarize() and thread it into _PROMPT_TEMPLATE
- Wire retrieve_context/format_context_block into diagnose_stream() before
log search; emit context SSE event (facts + chunks) to the client
- 3 new tests covering prompt injection and SSE event emission (155 total, all pass)
- Implement document type detection for yaml/json/markdown/text
- Extract service facts from docker-compose YAML (names, images, ports)
- Split text into overlapping word chunks (300-word default with 50-word overlap)
- Enforce 5 MB file size limit
- Comprehensive TDD test suite: 15 tests passing