feat: add changelog generation and GitHub release management}
- Add src/task/changelog module with Claude AI-powered changelog generation from git commit history across single and multi-repo workspaces - Add GitHub release creation/update support with draft promotion and untagged draft handling (github-release.js) - Register changelog module as a new task in src/task/index.js - Add type guard in src/loader.js to skip non-function task exports when iterating task entries - Auto-ensure .npmignore protects sensitive directories (secure/, agents/, .claude/, .vscode/, .codex/) during npm task execution - Bump version from 2025.4.136 to 2026.4.138 - Update Node.js version from v22.13.1 to v24.14.1 - Update dependencies: fs-extra, lodash, mocha, npm, npm-check-updates, yaml