docs: guide for sharing a Bot to the Bot Marketplace, with a copy-paste prompt #958

Problem

The product site's Bot Marketplace page (deepseekbot.botharness.ai/market) tells authors to "put the Bot's Memory in a public GitHub repository and add the botharness-bot topic", and links to the Worker README on GitHub for .botharness/bot.json. There is no user guide that walks a Human through sharing a Bot: what gets published, how to check it first, how to push it, and how to confirm it is listed.

What to build

A user guide docs/share-bot.md / docs/share-bot.zh.md (synced to deepseekbot.botharness.ai/docs/share-bot), with screenshots, covering:

1. What sharing publishes (the Bot's Memory Repository) and checking its files for anything private first (Memory files sidebar).
2. A one-click copy prompt the Human pastes to their own Bot, so the Bot checks its Memory, waits for confirmation, creates a public GitHub repository, pushes, and adds the botharness-bot topic.
3. The manual path (git / gh commands) for Humans who prefer it.
4. Listing right away by pasting the URL in Bot 市场, or waiting for the daily crawl; seeing it on the site.
5. .botharness/bot.json reference (name, roles, avatar image or recipe), moved here from the Worker README for authors.

The site's "想让你的 Bot 出现在这里？" card links to this guide instead of GitHub (deepseekbot-site change).

Acceptance criteria

• zh and en guides with screenshots (light), registered in scripts/sync-docs.mjs / the site's docs-pages.mjs
• Copyable prompt block; the prompt makes the Bot ask before publishing
• Privacy warning before publishing
• Site market card links to /docs/share-bot (and /en/docs/share-bot)

Blocked by

None. Whether .botharness/bot.json is generated automatically at Bot creation is a separate decision/issue; the guide follows whichever lands.