chore: bump version to 4.0.0

Author: Sam-Sims

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [4.0.0] - 2026-01-26
+
+### Changed
+
+- Summary output now lists identified taxon IDs in `taxons_identified` (replacing `total_taxon_count`)
+- Summary output now includes zero entries for identified taxa with no direct assignments in `reads_extracted_per_taxon`
+
 ## [3.1.0] - 2025-12-12
 
 ### Added
@@ -20,6 +27,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Kraken report/output parsing errors now include the line number and o line for easier debugging.
 
+## [4.0.0] - 2026-01-26
+
+### Changed
+
+- Summary output now lists identified taxon IDs in `taxons_identified` (replacing `total_taxon_count`) and includes zero
+  entries for identified taxa with no direct assignments in `reads_extracted_per_taxon`.
+
 ## [3.0.1] - 2025-10-16
 
 ### Fixed

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "kractor"
-version = "3.1.0"
+version = "4.0.0"
 edition = "2021"
 authors = ["Samuel Sims"]
 description = "Extract reads from a FASTQ file based on taxonomic classification via Kraken2."