Watcher, REST endpoints, services (search, incidents, blocklist),
MCP server, context retriever, embedder, glean_scheduler, and
doc_upload all used the default 5-second SQLite busy timeout.
During collect glean write phases, watcher flush threads were hitting
'database is locked' errors when the glean held the write lock longer
than 5 seconds.
All connections now use timeout=30.0, matching the pipeline fix
from commit 5a9281a. No logic changes.
- 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
