Prepare Python v0.3.0

Release the product-neutral SPSS-like transformation frontend and in-place executor as OpenStatSpec Python v0.3.0, pinned to specification v0.2.0.

Author: TonisOrmisson

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this reference implementation are documented here.
 
-## Unreleased
+## 0.3.0 — 2026-07-31
 
 ### Added
 

docs/release-readiness.md

@@ -1,4 +1,4 @@
-# Next release readiness
+# 0.3.0 release readiness
 
 This page records the expected release contract, not a publication event.
 Creating a version tag remains a separate maintainer action.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "openstatspec"
-version = "0.2.0"
+version = "0.3.0"
 description = "Reference adapter for the OpenStatSpec relational contract"
 readme = "README.md"
 requires-python = ">=3.11"