联网搜索响应超限的诊断带上实际收到的字节数

- WebSearchError::ResponseTooLarge 原来只记 max_bytes，用户只看到「超过上限 524288 bytes」，不知道实际多大
- 两个构造点都已拿到真实大小：content_length() 与 bytes.len() + chunk.len()，变体加 got_bytes 并写进文案
- 判定与两个构造点位置不变，仅补上实际值

验证：cargo test --bin genarrative-ai-game-creator-shell -- agent::direct_tool_bridge::tests::search_parser_accepts_only_bounded_public_https_results 通过

apps/ai-game-creator-shell/src-tauri/src/agent/direct_tool_bridge.rs

@@ -3452,11 +3452,12 @@ async fn bridge_web_search_at(
             status: response.status().as_u16(),
         });
     }
-    if response
+    if let Some(length) = response
         .content_length()
-        .is_some_and(|length| length > DIRECT_TOOL_BRIDGE_MAX_SEARCH_RESPONSE_BYTES as u64)
+        .filter(|length| *length > DIRECT_TOOL_BRIDGE_MAX_SEARCH_RESPONSE_BYTES as u64)
     {
         return Err(WebSearchError::ResponseTooLarge {
+            got_bytes: usize::try_from(length).unwrap_or(usize::MAX),
             max_bytes: DIRECT_TOOL_BRIDGE_MAX_SEARCH_RESPONSE_BYTES,
         });
     }
@@ -3470,8 +3471,10 @@ async fn bridge_web_search_at(
                 cause: error.to_string(),
             })?
     {
-        if bytes.len() + chunk.len() > DIRECT_TOOL_BRIDGE_MAX_SEARCH_RESPONSE_BYTES {
+        let received_bytes = bytes.len() + chunk.len();
+        if received_bytes > DIRECT_TOOL_BRIDGE_MAX_SEARCH_RESPONSE_BYTES {
             return Err(WebSearchError::ResponseTooLarge {
+                got_bytes: received_bytes,
                 max_bytes: DIRECT_TOOL_BRIDGE_MAX_SEARCH_RESPONSE_BYTES,
             });
         }

apps/ai-game-creator-shell/src-tauri/src/agent/tool/web_search/error.rs

@@ -18,7 +18,7 @@ pub(crate) enum WebSearchError {
     ClientUnavailable { cause: String },
     RequestFailed { cause: String },
     HttpStatusNotSuccess { status: u16 },
-    ResponseTooLarge { max_bytes: usize },
+    ResponseTooLarge { got_bytes: usize, max_bytes: usize },
     ResponseReadFailed { cause: String },
     NoPublicResults,
 }
@@ -62,8 +62,13 @@ impl ToolFailure for WebSearchError {
             Self::HttpStatusNotSuccess { status } => {
                 format!("联网搜索失败：AGC 受控搜索返回 HTTP {status}。")
             }
-            Self::ResponseTooLarge { max_bytes } => {
-                format!("联网搜索失败：AGC 受控搜索响应超过大小上限 {max_bytes} bytes。")
+            Self::ResponseTooLarge {
+                got_bytes,
+                max_bytes,
+            } => {
+                format!(
+                    "联网搜索失败：AGC 受控搜索响应有 {got_bytes} bytes，超过大小上限 {max_bytes} bytes。"
+                )
             }
             Self::ResponseReadFailed { cause } => {
                 format!("联网搜索失败：读取 AGC 受控搜索响应失败：{cause}")