release: version 0.5.9

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

.github/ISSUE_TEMPLATE/bug.yml

@@ -41,6 +41,6 @@ body:
     id: version
     attributes:
       label: Version and platform
-      placeholder: "v0.5.8 (or commit), macOS 15 arm64"
+      placeholder: "v0.5.9 (or commit), macOS 15 arm64"
     validations:
       required: true