Add Lark and Feishu official remote MCP plugins

[SamSokolin]

Resolves EXTY-1587

Packages the official hosted Lark and Feishu MCP servers for APJ Grok Bot connector demand (Nick Miller). Same URL-only HTTP shape as Attio and Statsig: no tokens, no client secrets, and no custom X-Lark-MCP-* headers.

Lark (international, required)

• Plugin: third_party/lark
• MCP URL: https://mcp.larksuite.com/mcp
• Auth: MCP OAuth Bearer, discovered at connect time. Unauthenticated initialize returns 401 (oauth required).
• Protected resource metadata: https://mcp.larksuite.com/.well-known/oauth-protected-resource/mcp
• Authorization server: https://accounts.larksuite.com/mcp (metadata at https://accounts.larksuite.com/.well-known/oauth-authorization-server/mcp)
• Dynamic client registration: https://open.larksuite.com/open-apis/app/v1/dcr
• Advertised tools/scopes: common (fetch-file-v2, get-user, search-user), docs (search/create/fetch/update doc, comments, list-docs-v2), IM (search-groups, get-group-members, get/search messages, get-thread-messages, get-read-status), offline_access

Feishu (China twin, same PR)

scripts/validate-plugins.mjs accepts the twin, so this PR ships it rather than leaving a follow-up.

• Plugin: third_party/feishu
• MCP URL: https://mcp.feishu.cn/mcp
• Authorization server: https://accounts.feishu.cn/mcp
• Dynamic client registration: https://open.feishu.cn/open-apis/app/v1/dcr
• Same advertised tool surface as Lark

Logo

Both plugins use the official Lark/Feishu bird mark published by Lark Technologies Pte. Ltd. on the larksuite GitHub organization. Feishu uses that same bird. The open-platform CDN was not reachable from this environment, so the mark was taken from that public organization avatar rather than redrawn.

Validation

node scripts/validate-plugins.mjs — all plugins validated successfully.