chore(hub): remove markdown_to_pdf tool (#3)

Drop markdown_to_pdf MCP surface, implementation, tests, and md-to-pdf dependency.

Roles that still list markdown_to_pdf must be cleaned before startup.

Co-authored-by: Hong Jiarong <me@jrhim.com>
Co-committed-by: Hong Jiarong <me@jrhim.com>

hub/admin-web/src/lib/constants.ts

@@ -18,7 +18,6 @@ export const TOOL_OPTIONS: ToolOption[] = [
 	{ id: 'feishu_read_context', label: '读飞书上下文', group: '飞书' },
 	{ id: 'feishu_download_resource', label: '下载飞书资源', group: '飞书' },
 	{ id: 'request_approval', label: '请求审批', group: '飞书' },
-	{ id: 'markdown_to_pdf', label: 'Markdown → PDF', group: '文档' },
 ];
 
 /** 组织成员角色（接口枚举保持英文，界面用 orgRoleLabel） */