feat(search): single-type projection, iterable quad input, blue/green collection name

[ddeboer]

Closes three API gaps that surfaced while migrating the Dataset Register indexer onto @lde/search / @lde/search-typesense, each of which forced a downstream workaround.

1. @lde/search: projectType(quads, searchType)

Projecting a single root type of a multi-type schema had no supported entry point: projectGraph frames every type, and building a one-type SearchSchema trips searchSchema()’s label-source validation — so consumers were forging the SearchSchema brand with as unknown as SearchSchema.

projectType scopes a projection to one root type — same framing and document shape — without building (and re-validating) a schema. projectGraph now delegates through the same framing core.

2. @lde/search: accept Iterable<Quad>

projectType and projectGraph now accept any Iterable<Quad>, not just a materialized array, so a caller merging several sources can pass a chained generator (function* () { yield* a; yield* b; }) instead of building a third full array at the projection peak.

Framing was refactored into buildSubjectIndex + frameSubjects: projectGraph scans the input once, building a single subject index every type frames off, rather than re-scanning the quads per type. This makes multi-type projection both single-pass and safe over a one-shot iterable.

3. @lde/search-typesense: expose the minted collection name

BlueGreenRebuild mints and swaps to ${name}_<timestamp> internally but did not report it, so a caller needing the concrete collection name had to issue an extra aliases().retrieve() after commit().

The run writer is now typed BlueGreenRunWriter, exposing the versioned collection as run.collection — fixed at openRun, before the first write — removing the round trip. (Exposed as a property rather than a commit() return value: the generic RunWriter.commit(): Promise<void> cannot be narrowed to Promise<string> through Promise<T>.)

Fix #579