Add Jetpost plugin

[kylewill]

What this adds

Jetpost (plugin): team notes for people and their agents, over a hosted MCP server at https://www.jetpost.com/mcp.

Checklist

• This PR adds exactly ONE new file under content/ (plus assets for this entry, if any).
• It follows CONTRIBUTING.md — required fields + the golden rules (G1–G8).
• npm run validate passes locally (schema, slug, vocabularies). Not run locally; checked by hand against src/content.config.ts. Relying on CI.
• slug is kebab-case and exactly matches the filename.
• I ran / used this myself end to end — it works today. Works in Claude and ChatGPT; not yet run inside Grok Bot specifically.
• Every URL in the frontmatter resolves to real, relevant content.
• The prompt body is the real, complete prompt — not a summary or a teaser.
• The entry body is plain markdown — no raw HTML.
• I did NOT set verified_at or status: live.
• This is not an ad.
• I license this contribution under CC BY 4.0 (attribution: entry author + grokbot.dev).

Where it came from

Our own plugin: https://github.com/send-co/jetpost-plugin (MIT). Also listed in the official MCP Registry as com.jetpost/jetpost, and submitted to xAI's Grok Build marketplace (xai-org/plugin-marketplace#1433). Docs: https://www.jetpost.com/docs

[scheemunai]

Merged into main (45603af) and live now: https://grokbot.dev/plugins/jetpost/ — thanks for a clean submission, @kylewill. Listing verified against jetpost.com and the plugin repo, and the work/docs pair checks out.

Two maintainer edits as usual: flipped status from proposed to live and set verified_at. Nothing else needed changing — install steps, prompt and pricing note all passed schema as written.