fix(server): keep earlier replies visible after agent resume (#9098)

* fix(server): keep earlier replies visible after agent resume

Idle runtime collection retains timeline rows but recreates provider sessions. Scope turn counters to a fresh UUID namespace so resumed sessions cannot reuse persisted turn identities.

* test(server): require a turn ID before inspecting its namespace

public-docs/plugins/hooks.md

@@ -94,7 +94,7 @@ type PluginTurnOutcome =
 
 | Field        | Shape / meaning                                                                        |
 | ------------ | -------------------------------------------------------------------------------------- |
-| `turnId`     | Provider-reported `string` or `null`; can repeat after a session reopens               |
+| `turnId`     | Provider-reported `string` or `null`; unique across resumed sessions                   |
 | `timeline`   | Deprecated, always `[]`; fetch history with the SDK.                                   |
 | `request`    | SDK `AgentPermissionRequest`; `kind` is `tool`, `plan`, `question`, `mode`, or `other` |
 | `resolution` | SDK `AgentPermissionResponse`                                                          |

public-docs/plugins/hooks.zh-CN.md

@@ -92,7 +92,7 @@ type PluginTurnOutcome =
 
 | 字段         | 结构 / 含义                                                                              |
 | ------------ | ---------------------------------------------------------------------------------------- |
-| `turnId`     | Provider 报告的 `string` 或 `null`；会话重新打开后可能重复                               |
+| `turnId`     | Provider 报告的 `string` 或 `null`；在会话恢复后仍保持唯一                               |
 | `timeline`   | 已弃用，始终为 `[]`；通过 SDK 获取历史。                                                 |
 | `request`    | SDK 的 `AgentPermissionRequest`；`kind` 为 `tool`、`plan`、`question`、`mode` 或 `other` |
 | `resolution` | SDK 的 `AgentPermissionResponse`                                                         |