Add release automation workflows and slash commands

[raj-khan]

Summary

• Adds 3 GitHub Actions workflows for end-to-end release automation:
  • release.yml - manual trigger (patch/minor/major), bumps all 4 package versions, opens PR
  • tag-on-merge.yml - creates git tag + GitHub Release when bump PR merges to main
  • publish.yml - publishes all 4 packages to npm when release is created (uses NPM_TOKEN secret)
• Adds .claude/commands/do-release.md - /do-release slash command that walks through the full release flow
• Adds .claude/commands/update-website.md - /update-website slash command to sync the site after each release
• Cleans up .claude/settings.local.json with consolidated wildcard permissions

Token storage

npm token is stored as a GitHub Secret NPM_TOKEN (never in code). Rotate it with:
```
gh secret set NPM_TOKEN --body NEW_TOKEN --repo learnkit-ai/learnkit
```

Usage

Next release: /do-release patch (or minor/major)