CI: fix changelog extraction regex to match ## Version / ## [X.Y.Z] headings

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: NookieAI

.github/workflows/build.yml

@@ -39,7 +39,7 @@ import re, sys
 ver = sys.argv[1]
 try:
     cl = open('CHANGELOG.md', encoding='utf-8').read()
-    m = re.search(r'## Version ' + re.escape(ver) + r'\b(.*?)(?=\n## |\Z)', cl, re.DOTALL)
+    m = re.search(r'^##\s*(?:Version\s+)?\[?v?' + re.escape(ver) + r'\]?\b.*?\n(.*?)(?=\n##\s|\Z)', cl, re.DOTALL | re.MULTILINE)
     print((m.group(1).strip()[:3000] if m else '').rstrip())
 except Exception as e:
     sys.stderr.write(str(e) + '\n')