chore(release): prepare 0.15.0 contract alignment release

Author: moonyue-w

CHANGELOG.md

@@ -5,6 +5,8 @@ existing `0.1.0` release; earlier development prereleases are not listed.
 
 ## [Unreleased]
 
+## [0.15.0]
+
 ### Added
 
 - Add typed Forward Session budgets across create/update responses and events, including omission, explicit null clearing and decimal-string limits.

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "qca-sdk"
-version = "0.14.0"
+version = "0.15.0"
 description = "Typed synchronous and asynchronous clients for Qoder Cloud Agents"
 authors = [{name = "Qoder"}]
 license = "MIT"