chore: re-scope npm package to @postkitstack/postkit

[nipunappri]

Branch:chore/rescope-npm-postkitstack → development

Summary

• Re-scopes the published npm package from @appritech/postkit to @postkitstack/postkit to match the new postkitstack npm org.
• Merges main into development so the appritechnologies → postkitstack GitHub-org rename (fix: issues on postkit skill, repo migration changes, minor docs #50, merged to main only) also lands on development.

Changes

• cli/package.json + cli/package-lock.json: package name → @postkitstack/postkit
• README.md, cli/README.md: install commands, npm version/license badges, npm package links
• docs/docs/getting-started/installation.md, docs/docs/intro.mdx, 3 docs/blog/* posts: npm install -g commands
• docs/blog/authors.yml: GitHub org URL (appritechnologies → postkitstack) — was missed by fix: issues on postkit skill, repo migration changes, minor docs #50
• Merge of main: brings fix: issues on postkit skill, repo migration changes, minor docs #50 (skill internal metadata, agent/skills/ → skills/ move, appritechnologies/postkit → postkitstack/Postkit references, docs updates)

Bin name (postkit) and version (1.3.2) are unchanged. No cli/src code changes — index.ts reads only version from package.json, not name.

Type of Change

• chore: Build, tooling, or CI changes

Test Plan

• Unit tests pass (npm run test)
• E2E tests pass (npm run test:e2e) (if applicable)
• Build succeeds (npm run build)
• Manually verified: no @appritech / appritechnologies references remain (git grep); package-lock.json regenerated and consistent; npm pkg get name → @postkitstack/postkit

Breaking Changes

• This introduces a breaking change

The published package name changes. Existing users must reinstall from the new name:

npm uninstall -g @appritech/postkit
npm install -g @postkitstack/postkit

The postkit command itself is unchanged.

Release follow-ups (not in this PR)

• NPM_TOKEN GitHub Actions secret must have publish rights to the @postkitstack npm org (release.yml already publishes with --access public --provenance).
• After the first release under the new name, deprecate the old package: npm deprecate @appritech/postkit "Moved to @postkitstack/postkit".
• Product/company naming left untouched by design: author: "Appri Team", "Appri stack" / "Appri Function Runtime" copy, title: Appri Technologies in authors.yml.