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/usage/logger.rs

@@ -16,6 +16,11 @@ pub struct RequestLog {
     pub app_type: String,
     pub model: String,
     pub request_model: String,
+    /// 写入时实际用于计价的模型名（pricing_model_source 解析后的结果）。
+    /// 落库供回填使用：缺价行补价后必须按写入时的基准重算，而不是
+    /// 用 model/request_model 猜——路由接管下三者可能各不相同。
+    /// 错误行（未计价）为空字符串。
+    pub pricing_model: String,
     pub usage: TokenUsage,
     pub cost: Option<CostBreakdown>,
     pub latency_ms: u64,
@@ -68,18 +73,19 @@ impl<'a> UsageLogger<'a> {
 
         conn.execute(
             "INSERT OR REPLACE INTO proxy_request_logs (
-                request_id, provider_id, app_type, model, request_model,
+                request_id, provider_id, app_type, model, request_model, pricing_model,
                 input_tokens, output_tokens, cache_read_tokens, cache_creation_tokens,
                 input_cost_usd, output_cost_usd, cache_read_cost_usd, cache_creation_cost_usd, total_cost_usd,
                 latency_ms, first_token_ms, status_code, error_message, session_id,
                 provider_type, is_streaming, cost_multiplier, created_at
-            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15, ?16, ?17, ?18, ?19, ?20, ?21, ?22, ?23)",
+            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15, ?16, ?17, ?18, ?19, ?20, ?21, ?22, ?23, ?24)",
             rusqlite::params![
                 log.request_id,
                 log.provider_id,
                 log.app_type,
                 log.model,
                 log.request_model,
+                log.pricing_model,
                 log.usage.input_tokens,
                 log.usage.output_tokens,
                 log.usage.cache_read_tokens,
@@ -129,6 +135,8 @@ impl<'a> UsageLogger<'a> {
             app_type,
             model,
             request_model,
+            // 错误行未经过计价，留空（回填的 has_usage 闸门也不会碰全 0 行）
+            pricing_model: String::new(),
             usage: TokenUsage::default(),
             cost: None,
             latency_ms,
@@ -168,6 +176,8 @@ impl<'a> UsageLogger<'a> {
             app_type,
             model,
             request_model,
+            // 错误行未经过计价，留空（回填的 has_usage 闸门也不会碰全 0 行）
+            pricing_model: String::new(),
             usage: TokenUsage::default(),
             cost: None,
             latency_ms,
@@ -203,13 +213,22 @@ impl<'a> UsageLogger<'a> {
         provider_id: &str,
         app_type: &str,
     ) -> (Decimal, String) {
-        let default_multiplier_raw = match self.db.get_default_cost_multiplier(app_type).await {
-            Ok(value) => value,
-            Err(e) => {
-                log::warn!("[USG-003] 获取默认倍率失败 (app_type={app_type}): {e}");
-                "1".to_string()
-            }
+        // Claude Desktop 网关没有独立的全局计费配置（proxy_config 的 CHECK 仅
+        // 允许 claude/codex/gemini，前端也只暴露三项），全局默认继承 claude；
+        // 供应商级 meta 覆盖仍按 claude-desktop 查找（providers 表按该 app_type 存）。
+        let default_app_type = if app_type == "claude-desktop" {
+            "claude"
+        } else {
+            app_type
         };
+        let default_multiplier_raw =
+            match self.db.get_default_cost_multiplier(default_app_type).await {
+                Ok(value) => value,
+                Err(e) => {
+                    log::warn!("[USG-003] 获取默认倍率失败 (app_type={app_type}): {e}");
+                    "1".to_string()
+                }
+            };
         let default_multiplier = match Decimal::from_str(&default_multiplier_raw) {
             Ok(value) => value,
             Err(e) => {
@@ -220,13 +239,14 @@ impl<'a> UsageLogger<'a> {
             }
         };
 
-        let default_pricing_source_raw = match self.db.get_pricing_model_source(app_type).await {
-            Ok(value) => value,
-            Err(e) => {
-                log::warn!("[USG-003] 获取默认计费模式失败 (app_type={app_type}): {e}");
-                PRICING_SOURCE_RESPONSE.to_string()
-            }
-        };
+        let default_pricing_source_raw =
+            match self.db.get_pricing_model_source(default_app_type).await {
+                Ok(value) => value,
+                Err(e) => {
+                    log::warn!("[USG-003] 获取默认计费模式失败 (app_type={app_type}): {e}");
+                    PRICING_SOURCE_RESPONSE.to_string()
+                }
+            };
         let default_pricing_source = if default_pricing_source_raw == PRICING_SOURCE_RESPONSE
             || default_pricing_source_raw == PRICING_SOURCE_REQUEST
         {
@@ -325,6 +345,7 @@ impl<'a> UsageLogger<'a> {
             app_type,
             model,
             request_model,
+            pricing_model,
             usage,
             cost,
             latency_ms,