refactor(proxy): improve header forwarding with blacklist approach

Change from whitelist to blacklist mode for request header forwarding.
Only skip headers that will be overridden (auth, host, content-length).
This preserves client's original headers and improves compatibility.

src-tauri/src/proxy/forwarder.rs

@@ -487,29 +487,17 @@ impl RequestForwarder {
         // 构建请求
         let mut request = self.client.post(&url);
 
-        // 只透传必要的 Headers（白名单模式）
-        let allowed_headers = [
-            "accept",
-            "user-agent",
-            "x-request-id",
-            "x-stainless-arch",
-            "x-stainless-lang",
-            "x-stainless-os",
-            "x-stainless-package-version",
-            "x-stainless-runtime",
-            "x-stainless-runtime-version",
-        ];
+        // 请求头黑名单：仅跳过会被覆盖或可能失效的字段（认证、Host、长度）
+        let skip_headers = ["authorization", "x-api-key", "host", "content-length"];
 
         for (key, value) in headers {
             let key_str = key.as_str().to_lowercase();
-            if allowed_headers.contains(&key_str.as_str()) {
-                request = request.header(key, value);
+            if skip_headers.contains(&key_str.as_str()) {
+                continue;
             }
+            request = request.header(key, value);
         }
 
-        // 确保 Content-Type 是 json
-        request = request.header("Content-Type", "application/json");
-
         // 使用适配器添加认证头
         if let Some(auth) = adapter.extract_auth(provider) {
             log::debug!(

src-tauri/src/services/usage_stats.rs

@@ -954,12 +954,22 @@ mod tests {
                 model_id, display_name, input_cost_per_million, output_cost_per_million,
                 cache_read_cost_per_million, cache_creation_cost_per_million
             ) VALUES (?, ?, ?, ?, ?, ?)",
-            params!["claude-haiku-4.5", "Claude Haiku 4.5", "1.0", "2.0", "0.0", "0.0"],
+            params![
+                "claude-haiku-4.5",
+                "Claude Haiku 4.5",
+                "1.0",
+                "2.0",
+                "0.0",
+                "0.0"
+            ],
         )?;
 
         // 测试精确匹配（seed_model_pricing 已预置 claude-sonnet-4-5-20250929）
         let result = find_model_pricing_row(&conn, "claude-sonnet-4-5-20250929")?;
-        assert!(result.is_some(), "应该能精确匹配 claude-sonnet-4-5-20250929");
+        assert!(
+            result.is_some(),
+            "应该能精确匹配 claude-sonnet-4-5-20250929"
+        );
 
         // 清洗：去除前缀和冒号后缀
         let result = find_model_pricing_row(&conn, "anthropic/claude-haiku-4.5")?;