Add open-ztd: file-first task board

[skeletor-js]

Summary

• Adds open-ztd to Community/ -- a file-first task board for Zo Computer
• Cards stored as markdown files with YAML frontmatter, backed by SQLite index
• Includes CLI (scripts/ztd.ts), shared library (scripts/lib.ts), zo.space Kanban UI and API routes (assets/routes/)
• Supports assignees, priorities, types, tags, due dates, comments, attachments, activity logs, drag-and-drop reordering, and auto-archiving

What's included

Community/open-ztd/
  SKILL.md              -- Skill definition and quick reference
  scripts/
    ztd.ts              -- CLI tool
    lib.ts              -- Shared library (parser, serializer, SQLite)
  references/
    guide.md            -- Full documentation (CLI, API, card fields, architecture)
  assets/routes/
    kanban.tsx           -- Drag-and-drop Kanban board (React + @dnd-kit)
    api-kanban.ts        -- List/create cards API
    api-kanban-wildcard.ts -- Detail, update, delete, comments, reorder API

Validation

bun run validate passes with no issues for this skill (all warnings are pre-existing External/ issues).

Built by @skeletor-js on Zo Computer.