chore: bump version to 0.2.13 and update CHANGELOG

Document the duplicate trailer username matching change in CHANGELOG.md
and promote package version from 0.2.11 to 0.2.13.

Change-Id: I58d83f909543ca5fc0cf79ad79ce902df68212a1
Co-developed-by: Cursor <noreply@cursor.com>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>

Author: jiangxin

CHANGELOG.md

@@ -5,6 +5,23 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.2.13] - 2026-02-24
+
+### Added
+
+- Add Antigravity IDE support
+  - Add `__CFBundleIdentifier` (com.google.antigravity) and `ANTIGRAVITY_AGENT` environment variable detection
+  - Enable tracking contributions from Antigravity IDE
+  - Add comprehensive test coverage for Antigravity environment variables
+
+### Changed
+
+- Match duplicate trailers by username instead of full user info when adding Co-developed-by
+  - Previously compared full "Name <email>" string, causing Cursor <noreply@cursor.com> and Cursor <cursoragent@cursor.com> to be treated as different users
+  - Now compare only the username part and ignore the email for deduplication
+  - Both usernames must be non-empty; correctly deduplicate same-identity different-email trailers
+  - Add extractUsernameFromTrailer function and test cases for Cursor scenario
+
 ## [0.2.11] - 2026-02-13
 
 ### Added

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ai-coding-workshop/commit-msg",
-  "version": "0.2.11",
+  "version": "0.2.13",
   "type": "module",
   "main": "dist/index.js",
   "bin": {