v1.3.2

v1.3.2 - exclude repo metadata from GitHub source archive

Bug fix release. The auto-generated Source code (zip) on the
Release page previously shipped 27 repository metadata files
(.github/, .agents/, .gitignore, LICENSE, CONTRIBUTING.md,
CHANGELOG.md, CLAUDE.md, README*.md) alongside the skill content.

Changes:
- .gitattributes with export-ignore for the metadata paths
- release.yml: build a clean <tag>.zip explicitly via git archive
- release.yml: verify step that fails the build on any leak
- SKILL.md / SKILL_CN.md: version 1.3.1 -> 1.3.2
- CHANGELOG.md: 1.3.2 entry