pgvector-knowledge-patch

# pgvector Knowledge Patch Baseline: pgvector through 0.7.4, covering `vector`, `halfvec`, `sparsevec`, and `bit`; IVFFlat and HNSW; standard distance operators; and basic index tuning. This patch covers the 0.8-guide and 0.8.0 additions plus the current reference and hosted-deployment guidance through pgvector 0.8.5. ## Reference index | Reference | Topics | | --- | --- | | [references/iterative-scans.md](references/iterative-scans.md) | Filtered HNSW and IVFFlat searches, scan modes and limits, result ordering, planner costing | | [references/indexing-and-storage.md](references/indexing-and-storage.md) | Type and index limits, sparse vectors, quantization, expression and partial indexes, omissions, maintenance | | [references/deployment.md](references/deployment.md) | PostgreSQL compatibility, source and container builds, portability, hosted version windows, build resources | ## Breaking compatibility change ### PostgreSQL 12 is no longer supported pgvector 0.8 requires PostgreSQL 13 or newer. Upgrade the database server before adopting the 0.8 line. Current source-build instructions pin pgvector 0.8.5, and published containers cover PostgreSQL 13 through 18. ```sh docker pull pgvector/pgvector:0.8.5-pg18-trixie ``` See [references/deployment.md](references/deployment.md) for container variants, portable compilation, and hosted-platform constraints. ## Iterative scans for filtered nearest-neighbor queries Approximate indexes retrieve candidates before PostgreSQL a...