tantivyr 0.1.0

• Initial release.
• tnt_index_df() indexes a data frame in one call (auto-schema).
• Explicit schema API: tnt_schema() with tnt_text(), tnt_i64(), tnt_u64(), tnt_f64(), tnt_bool(), tnt_date() and tnt_json().
• tnt_index() creates or opens on-disk and in-memory indexes.
• tnt_add(), tnt_commit(), tnt_delete() and tnt_update() provide incremental updates.
• tnt_search() returns a tibble with BM25 scores, structured filters (comparison expressions or Tantivy query strings), snippet highlighting and fast-field ordering; tnt_count() returns total match counts.
• Portuguese and English stemming and stop words, plus other Snowball languages.