Added

• SearchOptions execution controls for per-query timeouts, scoring-budget limits, and streaming result collection, with TopDocs.IsPartial and ScoreDoc.EstimatedBytes exposing partial-result and resource-use information.
• Field validation for document field names and vector inputs, plus coverage for invalid field, vector, and geo-point values.
• BKD-backed numeric range search with sparse numeric-index sourcing and brute-force fallback.
• Streaming merge infrastructure for postings, stored fields, term vectors, and doc-value flushing to reduce merge-time memory pressure.
• Concurrent writer support for vectors, geo points, and sorted doc values.
• Codec validation for RoaringBitmap and segment files, including headers, CRC32 footers, and orphan sidecar cleanup.
• Fault-injection, merge-equivalence, writer-equivalence, concurrent-field, and force-merge memory tests, plus a BKD numeric range benchmark.

Changed

• Field-sorted search now uses heap selection for top-N results rather than sorting the full candidate set.
• Segment merges now run IO outside the writer lock so indexing can continue during merge work.
• Query parsing now reports offsets more accurately and supports lenient parsing behaviour.
• DisjunctionMaxQuery instances are frozen for safer execution, and segment metadata snapshots clone all tracked fields.
• Numeric doc-value range computation now compares mixed-sign bit patterns in unsigned space.

Fixed

• PrefixQuery and WildcardQuery now return each matching document once when multiple matched terms occur in the same document.
• Durable commits now fail closed when fsync fails instead of reporting success.
• Recovery validates required segment files and codec headers, fails closed when no commit file is valid, and tolerates missing .del files for graceful degradation.
• Streaming postings merge now seeks the position section correctly during force merges.
• Concurrent indexing now preserves vector, geo-point, and sorted doc-value data.
• MMapDirectory now implements disposal correctly, and pending delete handling no longer drops deletion state.
• README collapse and per-query resource-control examples were corrected.