feat(baizhi-agent-toolkit): add Baizhi MCP plugin

[ct-jaryn]

Plugin type (required) / 插件类型（必填）

• UI Plugin / 是 UI 插件 — provides MCP Apps interactive pages
• Standard plugin / 普通插件（非 UI） — does not provide MCP Apps interactive pages
• Not applicable / 不适用 — repository-only changes

Affected plugin name(s) / 涉及的插件名称：baizhi-agent-toolkit

What / 改动内容

Add a community Baizhi MCP plugin and its English/Chinese marketplace entry so ZCode users can discover an optional integration for web search, webpage reading, and structured extraction. This adds five plugin files and only its own catalog entry, without hooks, commands, UI pages, local executables, automatic approvals, or host changes.

The remote Streamable HTTP configuration uses https://agent-toolkit.app.baizhi.cloud/mcp and Authorization: Bearer ${ZCODE_BAIZHI_API_KEY}. Users supply their own nonempty key through the environment that launches ZCode; this does not add a password form or keychain. ZCode may enable a newly installed marketplace plugin automatically; installation with a configured key can therefore initialize the remote connection and discover tools. The equivalent bilingual READMEs document setup, unset versus empty variables, automatic connection/discovery, data destinations, service quota/costs, permissions, and the limits of disabling/uninstalling. This is a community contribution by ct-jaryn, without a certification or partnership claim.

为 ZCode 插件市场增加可选的“百智云 / Baizhi MCP”条目及最小远程 MCP 插件。用户自行配置 Key；双语说明明确网络、费用和验证边界，不宣称产品核心内置或官方认证。

Verification / 验证

Rebased onto the current main and moved this new community plugin to external_plugins/baizhi-agent-toolkit/, with only its own source pointer changed in the root catalog, as required by the updated contribution rules. The five installable files and generated ZIP bytes remain exactly unchanged; version 0.1.0 has not been published. The new distribution generator marks the entry publisherType: community, independently of usage category utilities. This does not migrate any existing plugin or change host code.

Market base: f09f7d181bbd42b3ea6181248f4cb5cdaee0e007. Initial version is 0.1.0 in both manifests.

• pnpm install --frozen-lockfile --offline and pnpm build passed with pnpm 10.33.2.
• python3 scripts/validate.py, python3 scripts/build_dist.py, pnpm marketplace:local, and git diff --check passed; all 35 catalog entries validate/package.
• The current tests.test_catalog_classification tests passed, and the built entry is classified as community.
• The generated plugin ZIP contains exactly the five source files with matching bytes (10381 bytes; SHA-256 69d1de0ea875fab102022aa8c1d005b837f0ad491b409b4485442910c6bd958d).
• On 2026-10-13, a separate harness imported the actual ZCode plugin/marketplace/MCP adapter modules from source aac4755666d09fdcd70272fcf063c077a639015f (source version 3.15.1), using Node 24.21.0 and locked MCP client/server SDK 2.0.0. Forty-eight module checks passed, covering localized catalog parsing, registration, installation and exact cached files, discovery, unset/empty keys, native initialization/list/call, replacement credentials, disabled configuration, rediscovery, and uninstall. Nineteen HTTP requests went exclusively to a synthetic loopback MCP fixture; the unchanged vendor URL was mapped at the test transport boundary, and non-loopback requests were blocked.

Limits: These are local build and actual module/SDK checks, not a full desktop GUI or product CLI run, a released-host compatibility claim, remote CI, official market publication, or a live Baizhi/model test. No real service or model request was sent. The host's static marketplace validator uses an empty environment and reports plugin_variable_missing for this configuration even when the test process has the synthetic variable; this diagnostic is retained rather than reported as a passing validator. Runtime discovery using the supplied environment was tested separately. Desktop installation, environment inheritance and user approvals still need product-level validation.

Self-check / 自查清单

• Plugin name is unique kebab-case; new external plugin directory is external_plugins/<name>/
• Usage category is utilities, independent of community publisher classification
• Plugin type and affected names are declared above
• version is synchronized in BOTH plugin.json and marketplace.json (new plugin: initial 0.1.0)
• README.md (EN) and README_CN.md (中文) both updated and equivalent
• description_i18n has both en and zh-CN
• No secrets, machine-specific paths, or private dependencies
• Model/API/network dependencies documented
• python3 scripts/validate.py and python3 scripts/build_dist.py pass locally

[panda920]

✅ Internal validation passed. A ZCode maintainer will review the change next; after acceptance, release checks run separately and this PR is closed automatically.

[panda920]

✅ Internal validation passed. A ZCode maintainer will review the change next; after acceptance, release checks run separately and this PR is closed automatically.