refactor(types): request.rs 类型移入 provider/openai.rs

- 删除 types/request.rs（187 行）
- 所有 OpenAI wire-format 类型迁入 provider/openai.rs，可见性 pub(crate)：
  StreamOptions / OpenaiTool / AudioParam / PredictionContent / UserLocation /
  Approximate / WebSearchOptions / OpenaiChatRequest
- types/mod.rs 删除 pub mod request; 与对应 re-export
- convert_request 同步降级为 pub(crate) 以匹配 OpenaiChatRequest 可见性
- 公共 re-export 路径 agcore::llm::types::OpenaiChatRequest 等已删除（Breaking Change，见 CHANGELOG）

src/llm/provider/openai.rs

@@ -26,14 +26,127 @@ use crate::llm::convert::{from_openai, to_openai};
 use crate::llm::error::LlmError;
 use crate::llm::types::message::{ContentBlock, ContentBlockType, Message};
 use crate::llm::types::openai_message::{ContentField, OpenaiChatMessage};
-use crate::llm::types::request::{OpenaiChatRequest, OpenaiTool, StreamOptions};
 use crate::llm::types::request_v2::MessageRequest;
 use crate::llm::types::response::{OpenaiChatChunk, OpenaiChatResponse};
 use crate::llm::types::response_v2::{
     MessageResponse, PartialMessageResponse, PartialUsage, StopReason, StreamEvent,
 };
-use crate::llm::types::shared::FinishReason;
-use crate::llm::types::tool::OpenaiToolCall;
+use crate::llm::types::shared::{FinishReason, ResponseFormat, ServiceTier, StopSequence};
+use crate::llm::types::tool::{OpenaiToolCall, OpenaiToolDefinition, ToolChoice};
+use serde::Deserialize;
+
+// =============================================================================
+// 0. OpenAI wire-format 类型（Phase 13 从 types::request 迁入）
+// =============================================================================
+
+/// 流式响应选项。
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub(crate) struct StreamOptions {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub include_usage: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub include_obfuscation: Option<bool>,
+}
+
+/// OpenAI wire-format 工具定义。
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case", tag = "type")]
+pub(crate) enum OpenaiTool {
+    Function { function: OpenaiToolDefinition },
+}
+
+/// 音频输出参数。
+#[allow(dead_code)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub(crate) struct AudioParam {
+    pub format: String,
+    pub voice: String,
+}
+
+/// 预测内容（OpenAI `prediction` 字段）。
+#[allow(dead_code)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub(crate) struct PredictionContent {
+    #[serde(rename = "type")]
+    pub pred_type: String,
+    pub content: String,
+}
+
+/// 用户位置（web search 用）。
+#[allow(dead_code)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub(crate) struct UserLocation {
+    #[serde(rename = "type")]
+    pub loc_type: String,
+    pub approximate: Approximate,
+}
+
+/// 近似位置。
+#[allow(dead_code)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub(crate) struct Approximate {
+    pub city: String,
+    pub country: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub region: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub timezone: Option<String>,
+}
+
+/// Web search 选项。
+#[allow(dead_code)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub(crate) struct WebSearchOptions {
+    pub search_context_size: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub user_location: Option<UserLocation>,
+}
+
+/// OpenAI Chat Completions 请求体。
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub(crate) struct OpenaiChatRequest {
+    pub model: String,
+    pub messages: Vec<OpenaiChatMessage>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub frequency_penalty: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub logit_bias: Option<Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub max_tokens: Option<u32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub n: Option<u32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub presence_penalty: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub response_format: Option<ResponseFormat>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub seed: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub service_tier: Option<ServiceTier>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub stop: Option<StopSequence>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub stream: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub stream_options: Option<StreamOptions>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub temperature: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub top_p: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tools: Option<Vec<OpenaiTool>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_choice: Option<ToolChoice>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub parallel_tool_calls: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub user: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub extra_headers: Option<Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub extra_body: Option<Value>,
+}
 
 // =============================================================================
 // 1. GenericOpenaiProvider —— OpenAI-compatible 协议共用实现
@@ -210,7 +323,10 @@ impl GenericOpenaiProvider {
     ///
     /// 实现注意：先在函数顶部抽取出所有 needed 字段（clone 或 move），避免后续
     /// 部分移动 `request` 后无法借用其它字段。
-    pub fn convert_request(&self, request: MessageRequest) -> Result<OpenaiChatRequest, LlmError> {
+    pub(crate) fn convert_request(
+        &self,
+        request: MessageRequest,
+    ) -> Result<OpenaiChatRequest, LlmError> {
         // ponytail: 先抽取 / clone 所有 owned 字段，再访问 request.extra，
         // 避免部分移动导致后续 `&self` borrow 失败。
         let model = request.model.clone();