fix(proxy): bill route-takeover traffic by the real upstream model

The model mapped for takeover (env mapping, Claude Desktop routes,
Copilot normalization, Codex chat override) was discarded inside the
forwarder, so usage attribution depended entirely on the upstream
echoing it back. When the upstream omitted the model or mirrored the
client alias, kimi/glm tokens were recorded and priced as claude-*
(roughly 5-25x overstatement).

- capture the final outbound model in forward(), return it via
  ForwardResult, and store it on the request context
- attribution fallback order is now: upstream echo (empty string
  treated as missing) -> outbound model -> client-requested model
- 'request' pricing mode anchors to the outbound model instead of the
  pre-mapping client alias; unchanged when no mapping applies
- persist the resolved pricing_model on every usage row
- Claude Desktop rows now log app_type "claude-desktop" on streaming
  and transform paths too (was hardcoded "claude", silently dropping
  desktop provider pricing overrides and splitting the cost basis by
  the stream flag); its global pricing defaults inherit the claude
  config since proxy_config only allows claude/codex/gemini rows

src-tauri/src/proxy/forwarder.rs

@@ -38,6 +38,11 @@ pub struct ForwardResult {
     pub response: ProxyResponse,
     pub provider: Provider,
     pub claude_api_format: Option<String>,
+    /// 实际发往上游的模型名（路由接管/模型映射后的真值）。
+    ///
+    /// usage 归因不能依赖 ctx.request_model（映射前的客户端别名）：上游响应
+    /// 缺失 model 或回显别名时，接管流量会被记成 claude-* 并按其定价计费。
+    pub outbound_model: Option<String>,
     /// 活跃连接 RAII guard：随响应一起流转到 response_processor / handle_claude_transform，
     /// 最终被 move 进流式 body future（或非流式响应作用域），覆盖整个响应生命周期。
     pub(crate) connection_guard: Option<ActiveConnectionGuard>,
@@ -463,7 +468,7 @@ impl RequestForwarder {
                 )
                 .await
             {
-                Ok((response, claude_api_format)) => {
+                Ok((response, claude_api_format, outbound_model)) => {
                     // 成功：普通闭合熔断状态异步记录，避免阻塞流式首包返回；
                     // HalfOpen 探测仍同步等待，保证 permit 与熔断状态及时释放。
                     self.record_success_result(&provider.id, app_type_str, used_half_open_permit)
@@ -511,6 +516,7 @@ impl RequestForwarder {
                         response,
                         provider: provider.clone(),
                         claude_api_format,
+                        outbound_model,
                         connection_guard: None,
                     });
                 }
@@ -561,7 +567,7 @@ impl RequestForwarder {
                                 )
                                 .await
                             {
-                                Ok((response, claude_api_format)) => {
+                                Ok((response, claude_api_format, outbound_model)) => {
                                     log::info!(
                                         "[{app_type_str}] [Media] Unsupported-image retry succeeded"
                                     );
@@ -613,6 +619,7 @@ impl RequestForwarder {
                                         response,
                                         provider: provider.clone(),
                                         claude_api_format,
+                                        outbound_model,
                                         connection_guard: None,
                                     });
                                 }
@@ -706,7 +713,7 @@ impl RequestForwarder {
                                     )
                                     .await
                                 {
-                                    Ok((response, claude_api_format)) => {
+                                    Ok((response, claude_api_format, outbound_model)) => {
                                         log::info!("[{app_type_str}] [RECT-002] 整流重试成功");
                                         self.record_success_result(
                                             &provider.id,
@@ -761,6 +768,7 @@ impl RequestForwarder {
                                             response,
                                             provider: provider.clone(),
                                             claude_api_format,
+                                            outbound_model,
                                             connection_guard: None,
                                         });
                                     }
@@ -871,7 +879,7 @@ impl RequestForwarder {
                                 )
                                 .await
                             {
-                                Ok((response, claude_api_format)) => {
+                                Ok((response, claude_api_format, outbound_model)) => {
                                     log::info!("[{app_type_str}] [RECT-011] budget 整流重试成功");
                                     self.record_success_result(
                                         &provider.id,
@@ -920,6 +928,7 @@ impl RequestForwarder {
                                         response,
                                         provider: provider.clone(),
                                         claude_api_format,
+                                        outbound_model,
                                         connection_guard: None,
                                     });
                                 }
@@ -1077,6 +1086,9 @@ impl RequestForwarder {
     }
 
     /// 转发单个请求（使用适配器）
+    ///
+    /// 成功时返回 `(response, claude_api_format, outbound_model)`，其中
+    /// `outbound_model` 是最终发往上游的模型名（所有映射/改写之后）。
     #[allow(clippy::too_many_arguments)]
     async fn forward(
         &self,
@@ -1088,7 +1100,7 @@ impl RequestForwarder {
         headers: &axum::http::HeaderMap,
         extensions: &Extensions,
         adapter: &dyn ProviderAdapter,
-    ) -> Result<(ProxyResponse, Option<String>), ProxyError> {
+    ) -> Result<(ProxyResponse, Option<String>, Option<String>), ProxyError> {
         // 使用适配器提取 base_url
         let mut base_url = adapter.extract_base_url(provider)?;
 
@@ -1320,6 +1332,15 @@ impl RequestForwarder {
             adapter.build_url(&base_url, &effective_endpoint)
         };
 
+        // 记录映射后的出站模型名（此时 mapped_body 已完成接管映射 / [1m] 剥离 /
+        // Copilot 归一化）。格式转换后若 body 仍带 model 字段会在下方刷新覆盖；
+        // gemini_native 等模型在 URL 中的格式则保留此处的转换前真值。
+        let mut outbound_model = mapped_body
+            .get("model")
+            .and_then(|m| m.as_str())
+            .filter(|m| !m.is_empty())
+            .map(str::to_string);
+
         // 转换请求体（如果需要）
         let mut request_body = if codex_responses_to_chat {
             let mut mapped_body = mapped_body;
@@ -1366,6 +1387,14 @@ impl RequestForwarder {
         // 过滤私有参数（以 `_` 开头的字段），防止内部信息泄露到上游
         // 默认使用空白名单，过滤所有 _ 前缀字段
         let filtered_body = prepare_upstream_request_body(request_body);
+        // 出站 body 定稿后刷新真值（覆盖 Codex chat 上游模型覆写、转换层模型改写）
+        if let Some(m) = filtered_body
+            .get("model")
+            .and_then(|m| m.as_str())
+            .filter(|m| !m.is_empty())
+        {
+            outbound_model = Some(m.to_string());
+        }
         log_prompt_cache_trace(
             app_type,
             provider,
@@ -1878,7 +1907,7 @@ impl RequestForwarder {
             let response = self
                 .prepare_success_response_for_failover(response, request_is_streaming)
                 .await?;
-            Ok((response, resolved_claude_api_format))
+            Ok((response, resolved_claude_api_format, outbound_model))
         } else {
             let status_code = status.as_u16();
             let body_text = String::from_utf8(response.bytes().await?.to_vec()).ok();