Shared query-construction brick (filter + fields → LIFQuery)

[bjagg]

Part of the ADR-0003 epic #1105. Plan: docs/operations/proposals/advisor-qp-direct-retrieval.md (PR #1104). Decision: ADR-0003.

Goal: Own query construction once — avoid forking it (ADR-0003 cost #1).

Scope:

• Extract "semantic filter + ranked dotted field paths → LIFQuery{filter, selected_fields}" into a shared brick.
• semantic-search builds a GraphQL string today (components/lif/semantic_search_service/core.py:411-422); the resolver builds LIFQuery JSON (components/lif/openapi_to_graphql/type_factory.py:807-809). Refactor both to construct LIFQuery through the brick.

Size: M · Depends on: B

[bjagg]

Scope correction from the PR #1104 review: this is more than assembling a LIFQuery. semantic-search builds a dynamically-built Pydantic filter (build_dynamic_filter_model, semantic_search_service/core.py:84) and serializes it to a GraphQL string; the QP wants a fixed LIFQueryFilter (RootModel[LIFQueryPersonFilter], datatypes/core.py:88). The shared brick must translate the dynamic filter model into the QP's filter model — that translation is the real work. Re-sized M → L.