Establish how semantic vector "coverage" is counted: current-model
embeddings over embed-eligible items, per media type, from Postgres.
- Move the embed-eligibility predicate to a single source of truth in
embeddingvectors.ItemEligibilityWhereClause; recommendations now
delegates to it (output byte-identical).
- Add catalogSemanticCoverageByType (per-type eligible/vectorized) and
define the coverageQuerier interface in catalog. Both numerator and
denominator apply the eligibility predicate, so vectorized never
exceeds eligible (C1 guarantee) even with a stale embedding on a
now-unmatched item.
- countCatalogSearchVectorDocuments now takes a coverageQuerier and a
model, applies the eligibility + model filter, and is the per-type
numerator summed across types. Update all four callers (pass "").
- Add idx_media_item_embeddings_model (CONCURRENTLY, self-healing
guard) so the model filter does not scan the embeddings table.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
