Version 0.4.0 (#330)

Minor bump: new capabilities since 0.3.2 and one breaking change
(legacy command ids are no longer accepted).


Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.toml

@@ -5,7 +5,7 @@ members = ["crates/*", "apps/*", "xtask"]
 exclude = ["vendor"]
 
 [workspace.package]
-version = "0.3.2"
+version = "0.4.0"
 edition = "2024"
 license = "MIT OR Apache-2.0"
 rust-version = "1.95"