chore(release): v2.4.0 (#148)

Bump workspace version 2.3.0 -> 2.4.0 and finalize the CHANGELOG for the
post-2.3.0 hardening release: three adversarial audits (operability 24,
untrusted-input security 4, concurrency/atomicity 4), all fixed and validated
end-to-end on real microVMs (composed-main CI Integration, a 2h/4584-op
zero-leak soak, and complex stateful containers). No breaking API changes.

Co-authored-by: Roy Lin <roylin@a3s.box>

Author: ZhiXiao-Lin

CHANGELOG.md

@@ -4,9 +4,14 @@ All notable changes to A3S Box will be documented in this file.
 
 ## [Unreleased]
 
+## [2.4.0] — 2026-06-17
+
 Post-2.3.0 hardening: three adversarial audits — production-operability (24
 findings), untrusted-input security (4), and concurrency/atomicity (4) — all
-fixed and validated on real microVMs. No breaking API changes.
+fixed and validated on real microVMs (composed-main real-VM CI Integration, a
+2-hour / 4584-op endurance soak with zero leak, and complex stateful containers:
+volume persistence, a stateful database across restart, and a web server). No
+breaking API changes.
 
 ### Security
 

src/Cargo.lock

@@ -22,7 +22,7 @@ resolver = "2"
 h2 = { path = "third_party/h2" }
 
 [workspace.package]
-version = "2.3.0"
+version = "2.4.0"
 edition = "2021"
 authors = ["A3S Lab Team"]
 license = "MIT"