docs(web-search): record client integration

.project-docs/40-domain/business-rules.md

@@ -38,6 +38,14 @@
   not expose Provider credentials, URLs, credit balances, raw responses, or Provider job
   IDs. Saving a hosted result must use bounded project-relative paths and the existing
   project write lease.
+- Native Web Search is a user-acquired `platform_hosted` Marketplace Plugin. Free
+  acquisition, device installation, project enablement, Agent assignment, current
+  Admission, and explicit per-search Token Point confirmation are separate gates.
+  Only the frozen parent worker receives `makelore_web_search`; child workers receive
+  no hosted tool. `submission_unknown` is result-less and must not auto-retry, while
+  `receipt_unavailable` is a Main-only closed billing projection that tells the user
+  not to repeat the search. Provider key, model, URL, price authority, and raw response
+  never enter Renderer, the Package, Pi arguments, or project metadata.
 - 面向用户的 AI 编程新建流程必须在 `mini_game`、`mini_program`、`custom` 中选择；`ProjectType` 是产品类型，创建后不能通过 UI 或 Host API 修改，未传类型的兼容 API 调用按 `custom` 处理。
 - 新建小游戏和小程序会生成平台固定版本的受控 Vite 发布模板，并可使用项目配置中的单一“提交审核”入口；`custom` 和缺少类型字段的旧项目不提供一键发布。
 - `ProjectType` 不等于 `BuildPreset`：第一期两个可发布产品类型都映射到内部受控 Vite preset；本地 `projectType` 不是授权边界，Main-owned 安全打包、Host API 和服务端包体校验仍必须执行。