feat(browser): W4-C BrowserProvider contract and camofox-browser adapter skeleton

- contracts/browser.ts: provider kind, per-capability {supported, verified} flags,
  session/tab/control-lease rows, NavigationBudget, redacted BrowserSnapshot,
  DownloadArtifact with blob/secret refs, BrowserErrorKind
- adapters/browser: BrowserProvider interface, camofox client (health, capabilities
  static + /openapi.json probe, openSession/navigate/snapshot/screenshot; rest
  not_implemented for M2), none provider, redactSnapshot, profile serial lock,
  domain allowlist budget; Bearer access key via BrowserSecretResolver
- testkit/browser: mock camofox server (auth, fixtures with secrets, faults)
- db 0023: browser_provider/session/tab/control_lease with one-active-lease and
  one-live-session-per-profile partial unique indexes; types regenerated
- docs/design/browser-provider.md: contract, camofox OpenAPI 1.17.0 mapping,
  unverified items and M2 prototype checklist; Playwright is not a product browser

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/adapters/src/browser/README.md

@@ -0,0 +1,26 @@
+# browser
+
+`BrowserProvider` 合同(`provider.ts`)及其实现:业务侧访问浏览器服务只走这套接口。产品浏览器能力对接用户已有的 camofox-browser;**Playwright 只用于前端截图测试,不是产品浏览器能力**。设计说明见 `docs/design/browser-provider.md`。
+
+- `camofox/`:camofox-browser 适配器。按 jo-inc/camofox-browser master `openapi.json`(1.17.0)与 README 实现,`Authorization: Bearer <CAMOFOX_ACCESS_KEY>`,凭据每次请求经 `BrowserSecretResolver` 解出,不缓存、不入日志。camofox `userId` = 本项目 `profileKey`(站点/账号隔离),`sessionKey` = `browser_session.id`。
+- `none.ts`:默认实现(未配置浏览器),能力全关,动作报 `unavailable`。
+- `redact.ts`:`redactSnapshot` / `redactBrowserUrl`,快照与地址进入模型前遮蔽密码框值、Cookie 值、含 passkey/token 的 URL。
+- `profile-lock.ts`:同一 profile 串行锁(进程内内存实现;多进程部署换持久化实现,接口不变)。
+- `budget.ts`:导航域名白名单(含子域),非 http(s) 拒绝。
+
+## v0.1 已实现
+
+`health`(`/health`,免认证,503 → degraded)、`capabilities`(静态声明;`probe: true` 读上游 `/openapi.json` 推导,缺端点即降级)、`openSession`(`POST /tabs`)、`navigate`(`POST /tabs/{id}/navigate`,预算内重试 5xx/超时/网络错误)、`snapshot`(`GET /tabs/{id}/snapshot?format=text`,字节预算截断 + 脱敏)、`screenshot`(`GET /tabs/{id}/screenshot`,JSON base64 或二进制图片;登录页/含凭据地址标 `modelSafe: false`)。
+
+## M2(当前抛 `BrowserError('not_implemented')`)
+
+| 方法 | 上游候选端点 | 待办 |
+| --- | --- | --- |
+| `closeSession` | `DELETE /sessions/{userId}` | 与 browser_session 持久化、租约释放一起落地 |
+| `listSessions` | `GET /tabs?userId=` | 上游只列标签页,会话清单以 DB 为准,需对账 |
+| `click` / `type` | `POST /tabs/{id}/click` / `type` / `select` | 接凭证代理(`TypeInput.kind = 'secret'`);README 示例 `pressEnter` 与 OpenAPI `submit` 字段名不一致,需核验 |
+| `extract` | `POST /tabs/{id}/extract`(JSON Schema + `x-ref`) | 需先 snapshot 建 ref 表 |
+| `waitForDownload` | `GET /tabs/{id}/downloads?includeData&consume&maxBytes` | 产物落 blob 暂存 + sha256,交后端核验 |
+| `acquireControl` / `releaseControl` | 无(上游无接管 API) | 服务层以 `browser_control_lease` 持久化;画面/输入通道待 VNC 原型 |
+
+仅对 mock 与上游文档验证,未连接真实实例。