fix(server): a plugin decides which options it applies live

A plugin reporting `controls` and `providerOptions` receives every key a live
change touches, with or without a control, and applies them or rejects the
whole request. The daemon's live-key guard now runs only for a plugin still
reporting `settings`, which cannot refuse a key.

public-docs/plugins/providers.md

@@ -275,9 +275,11 @@ at the default and values nobody set. The same controls appear in the New worksp
 tabs, and on running agents. Offer a control only for a key you can change on a running session.
 The provider may change its controls at runtime, including after a model change.
 
-A user change arrives as `session.configure` with `changes.providerOptions` holding only the keys
-that changed. Apply the change and publish the committed `session.config` before
-`request.completed`, or fail the request with `request.failed` and leave every key as it was. A
+A change arrives as `session.configure` with `changes.providerOptions` holding only the keys
+that changed, whether or not they have a control. Apply every key and publish the committed
+`session.config` before `request.completed`. Fail the request with `request.failed` and leave
+every key as it was when you cannot apply one, for example a key you read only when a session
+opens. A
 value of `null` returns that key to the provider's default. Publish what the session ended up
 with, not a copy of the request: Paseo stores your published values so the stored options match
 what runs.
@@ -286,8 +288,10 @@ If the provider changes an option on its own, for example a model switch turns F
 a new `session.config` with the new values. Paseo stores them and does not set the old ones
 back.
 
-Keys without a control are still delivered in `session.open` and stored. A provider-specific
-token budget, for example, belongs in `providerOptions` and is not a dedicated prompt field.
+Not every option needs a control. A provider-specific token budget, for example, belongs in
+`providerOptions` and is not a dedicated prompt field. It is delivered in `session.open`, a caller
+can change it on a running agent, and your `session.configure` handler decides whether it can
+apply it live. Report it in `providerOptions` so Paseo stores what runs.
 
 ## Add persistence and replay
 

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

@@ -244,11 +244,11 @@ emit({
 
 `icon` 是 Lucide 图标名称。`defaultValue` 是控件在键没有值时显示的值。会话打开或应用修改时，你报告的每个值（包括处于默认值的值和无人设置过的值）Paseo 都会保存。相同的控件会出现在“新建工作区”界面、草稿标签页和运行中的 Agent 上。只为你能在运行中的会话里修改的键提供控件。Provider 可以在运行时改变控件，包括在模型变化之后。
 
-用户的修改会以 `session.configure` 的形式到达，`changes.providerOptions` 只包含发生变化的键。应用它，并在 `request.completed` 之前发布已确定的 `session.config`；或者用 `request.failed` 使请求失败，并让每个键保持原样。值为 `null` 表示把该键恢复为 Provider 的默认值。请发布会话最终实际使用的值，而不是请求的副本：Paseo 会保存你发布的值，使保存的选项与实际运行的一致。
+修改会以 `session.configure` 的形式到达，`changes.providerOptions` 只包含发生变化的键，无论这些键是否有控件。应用每一个键，并在 `request.completed` 之前发布已确定的 `session.config`。如果无法应用其中某个键（例如只在会话打开时读取的键），用 `request.failed` 使请求失败，并让每个键保持原样。值为 `null` 表示把该键恢复为 Provider 的默认值。请发布会话最终实际使用的值，而不是请求的副本：Paseo 会保存你发布的值，使保存的选项与实际运行的一致。
 
 如果 Provider 自行改变了某个选项（例如切换模型后关闭了 Fast），请发布带有新值的 `session.config`。Paseo 会保存它们，不会把旧值设置回去。
 
-没有控件的键仍会在 `session.open` 中交付并被保存。例如 Provider 专属的 token 预算应放在 `providerOptions` 中，它不是一个专门的提示词字段。
+并非每个选项都需要控件。例如 Provider 专属的 token 预算应放在 `providerOptions` 中，它不是一个专门的提示词字段。它会在 `session.open` 中交付，调用方可以在运行中的 Agent 上修改它，由你的 `session.configure` 处理程序决定能否实时应用。请在 `providerOptions` 中报告它，使 Paseo 保存实际运行的值。
 
 ## 添加持久化与重放 {#add-persistence-and-replay}