Add a path_prefix filter to semantic search, honoured on both the MCP tool and
the dense-only visualization/API paths through the shared filter contract.
- build_base_filter_conditions: append FieldCondition(file_path,
MatchText(path_prefix)) when set. file_path is only on doc_type == "file"
points, so a non-empty path_prefix implicitly restricts to files.
- Promote path_prefix to an explicit keyword param on the SearchAlgorithm ABC
and both algorithms; thread it through nc_semantic_search (blank ⇒ no filter),
the /api/v1 search endpoints, and the viz route.
- Add a file_path TEXT payload index to _PAYLOAD_INDEX_FIELDS (no content
re-index; idempotent startup migration). MatchText tokenizes on server Qdrant
and matches by substring on local/embedded qdrant-client — both serve folder
scoping.
- Update ADR-027 (Phase 2 implemented; readiness table; semantics note). Tests.
Refs ADR-027 Phase 2. Deck #177.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>