ext-fts 0.3.0

ext-fts: Full-text search extension via tantivy.

Provides BM25-ranked full-text search through three procedures:

• fts.add(content) → indexes a document, returns {doc_id: INT64}
• fts.search(query, limit?) → BM25 ranked results {doc_id, score, snippet}
• fts.clear() → resets the index

Uses an in-memory tantivy index with batched commits (every 1000 documents). The index is thread-safe via Mutex<FtsIndex>.