feat(search)!: engine- and domain-agnostic query model, Typesense compiler, and GraphQL surface

[ddeboer]

What

Reworks @lde/search and @lde/search-typesense into a unified, engine- and
domain-agnostic search API, and adds @lde/search-api-graphql (the new GraphQL surface).
@lde/search and @lde/search-typesense already existed in the repo; this reworks them
(breaking), it does not introduce them. One declarative SearchSchema drives projection, the
engine collection schema, the query semantics, and the GraphQL surface – so they cannot drift. The domain type (Dataset,
Person, …) and the engine choice (Typesense, …) are the consumer’s, configured at the
seams; the libraries never name a domain.

Packages

@lde/search (core) — breaking

• Unifies the field model: one SearchField / SearchSchema replaces the projection
  FieldSpec/Projection and the discriminated FieldKind.
• Adds the neutral query IR (SearchQuery / Filter / Sort) and filter-operator semantics.
• Adds the SearchEngine port and logical result types (SearchResult / SearchHit /
  ResultDocument / Reference / LocalizedValue / FacetBucket).
• Adds physicalFields (the shared physical-fanout convention) and schema selectors
  (searchableFields, facetableFields, filterableFields, sortableFields, outputFields).
• Rewrites projectDocument/projectGraph onto the unified model; projection output is
  unchanged — the guardrail test was ported field-for-field.
• BREAKING: FieldSpec, Projection, and the discriminated FieldKind are removed.

@lde/search-typesense (engine adapter) — additive

• buildCollectionSchema derives a Typesense collection from the field model (kind→type, the
  physical fanout via physicalFields, per-locale stemming, required / default-sorting-field).
• buildSearchParams compiles SearchQuery into Typesense params — filter_by / sort_by /
  facet_by / query_by with active-locale weighting, grouped-facet OR, and exact membership
  for non-facet fields.
• createTypesenseSearchEngine implements the SearchEngine port end to end: it reconstructs
  logical documents and resolves reference (and reference-facet) labels from the sidecar
  labels collection in a single lookup.
• Covered by unit tests plus a Typesense testcontainer integration test.

@lde/search-api-graphql (GraphQL surface) — new

• buildSearchSchema(schema, { typeName }) builds an executable GraphQLSchema at runtime
  from any SearchSchema (no codegen, no SDL artifact), served by one generic resolver over
  any SearchEngine.
• Derives output types, where/orderBy/facet inputs, named reference types, and nullability
  (from required / array / kind) from the field model; best-first Accept-Language
  output ordering; a nullable facet label resolved for reference facets only.
• Exports printSearchSchema for a consumer-side SDL snapshot guard.

Notes

• ADRs 0003/0004 updated: the unified model, the SearchEngine rename (the interface is the
  port; the Typesense class is the adapter), size → Float (int64 overflow), the
  typed-surface design, and facet labels.
• Each generator ships a neutral-fixture snapshot to pin its output across versions.
• Deferred: the idOnly/inline reference strategies, the OutputOf<S> typed-surface
  overlay, and a REST surface.