feat(skills/notion): overhaul for Notion Developer Platform (May 2026)

[teknium1]

Summary

Brings the Notion skill up to date with Notion's May 13 2026 Developer Platform launch: ntn CLI, Workers, Markdown API, bidirectional webhooks.

Preserves the cross-platform curl path as the default — ntn is macOS/Linux only as of release, so Windows users keep a fully working pathway.

Changes

• skills/productivity/notion/SKILL.md: v1.0.0 → v2.0.0
  • Three setup paths: HTTP token (all OSes), ntn login (mac/Linux keychain), headless NOTION_API_TOKEN env var (CI / WSL / servers)
  • Adds /v1/pages/:id/markdown GET/PATCH and POST /v1/pages with markdown body — agent-friendly page I/O without any CLI
  • Adds ntn CLI cheat sheet (raw ntn api, file uploads, workspace flags)
  • Adds Notion Workers section (scaffold, tool/webhook capability shape, lifecycle commands) — gated on Business/Enterprise + mac/Linux
  • Adds Notion-flavored Markdown reference (callouts, toggles, columns, mentions, colors)
  • Adds 'choose the right path' decision table
  • Note on the now-efficient Notion MCP server as an optional wiring
• website/docs/user-guide/skills/bundled/productivity/productivity-notion.md: regenerated via website/scripts/generate-skill-docs.py

Validation

• Existing curl examples preserved verbatim — no breaking changes for current users
• Windows pathway documented explicitly (Path A + Path C section)
• All new endpoints/commands sourced from current notion.dev docs (cross-checked: developers.notion.com/cli, /workers, /guides/data-apis/enhanced-markdown)
• platforms: [linux, macos, windows] retained — curl path works on all three