feat(template-editor): add new template editing component

[mttrbrts]

Summary

• Removes four deprecated packages (ui-components, ui-contract-editor, ui-markdown-editor, storybook) that were based on Slate.js and had fallen out of active maintenance
• Adds @accordproject/ui-tiptap-template-editor — a new TypeScript-first template editor built on TipTap v2 / ProseMirror, covering all TemplateMark node types
• Adds ui-tiptap-template-editor-demo — a Vite + React playground for local development of the editor
• Updates ui-concerto dependencies and test snapshots to work in the slimmed-down monorepo
• Cleans up root package.json, removes lerna.json, and updates CI workflows to reflect the new package structure

Key changes

Area	Detail
New editor	packages/ui-tiptap-template-editor — extensions for all TemplateMark nodes (Variable, Formula, Clause, Conditional, Optional, ListBlock, Foreach, …), serializer round-trips, validation
via TemplateMarkTransformer, modelManager prop for external Concerto models
Demo app	packages/ui-tiptap-template-editor-demo — NDA and Services Agreement fixtures, JSON panel, hot-reload alias to editor source
Removed packages	ui-components, ui-contract-editor, ui-markdown-editor, storybook — all deleted
CSS bundling	postcss-import added to rollup config so @import directives in CSS are inlined at build time (fixes CSS variable injection in downstream consumers)
CI	build-and-deploy.yml removed (storybook deploy); build.yml and publish.yml updated for the new package

Test plan

• cd packages/ui-tiptap-template-editor && npm run build — clean build
• cd packages/ui-tiptap-template-editor && npm test — serializer round-trip tests pass
• cd packages/ui-tiptap-template-editor-demo && npm run dev — demo loads at localhost:5174, NDA and Services Agreement templates both validate correctly
• cd packages/ui-concerto && npm test — existing concerto form tests still pass

Screenshots or Video

Kapture.2026-03-13.at.09.44.37.mp4

Related Issues

• Issue #
• Pull Request #

Author Checklist

• Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• Vital features and changes captured in unit and/or integration tests
• Commits messages follow AP format
• Extend the documentation, if necessary
• Merging to master from fork:branchname
• Manual accessibility test performed
  • Keyboard-only access, including forms
  • Contrast at least WCAG Level A
  • Appropriate labels, alt text, and instructions