fix: stabilize puzzle vector engine asset generation

server-rs/crates/platform-image/src/vector_engine/transport.rs

@@ -11,6 +11,7 @@ pub fn build_vector_engine_image_http_client(
     reqwest::Client::builder()
         .timeout(Duration::from_millis(settings.request_timeout_ms.max(1)))
         .http1_only()
+        .pool_max_idle_per_host(0)
         .build()
         .map_err(|error| PlatformImageError::InvalidConfig {
             provider: VECTOR_ENGINE_PROVIDER,
@@ -29,7 +30,14 @@ pub(super) fn map_reqwest_error(
 ) -> PlatformImageError {
     let is_timeout = error.is_timeout();
     let is_connect = error.is_connect();
-    let source = error.source().map(ToString::to_string);
+    let source_chain_parts = collect_error_source_chain(&error);
+    let source = source_chain_parts.first().cloned();
+    let source_chain_depth = source_chain_parts.len();
+    let source_chain = if source_chain_parts.is_empty() {
+        None
+    } else {
+        Some(source_chain_parts.join(" -> "))
+    };
     let message = format!("{context}：{error}");
     let audit = build_failure_audit(
         request_url,
@@ -40,7 +48,7 @@ pub(super) fn map_reqwest_error(
         is_timeout,
         is_connect,
         message.as_str(),
-        source.clone(),
+        source_chain.clone().or_else(|| source.clone()),
         None,
         Some(latency_ms),
         prompt_chars,
@@ -56,6 +64,8 @@ pub(super) fn map_reqwest_error(
         body = error.is_body(),
         status = error.status().map(|status| status.as_u16()).unwrap_or_default(),
         source = %source.clone().unwrap_or_default(),
+        source_chain = %source_chain.clone().unwrap_or_default(),
+        source_chain_depth,
         message = %message,
         elapsed_ms = latency_ms,
         prompt_chars,
@@ -72,7 +82,62 @@ pub(super) fn map_reqwest_error(
         request: error.is_request(),
         body: error.is_body(),
         status_code: error.status().map(|status| status.as_u16()),
-        source,
+        source: source_chain.or(source),
         audit: Some(audit),
     }
 }
+
+fn collect_error_source_chain(error: &(dyn Error + 'static)) -> Vec<String> {
+    let mut chain = Vec::new();
+    let mut next = error.source();
+    while let Some(source) = next {
+        chain.push(source.to_string());
+        next = source.source();
+    }
+    chain
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fmt;
+
+    #[derive(Debug)]
+    struct TestError {
+        message: &'static str,
+        source: Option<Box<TestError>>,
+    }
+
+    impl fmt::Display for TestError {
+        fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+            formatter.write_str(self.message)
+        }
+    }
+
+    impl Error for TestError {
+        fn source(&self) -> Option<&(dyn Error + 'static)> {
+            self.source
+                .as_deref()
+                .map(|source| source as &(dyn Error + 'static))
+        }
+    }
+
+    #[test]
+    fn collect_error_source_chain_keeps_nested_causes() {
+        let error = TestError {
+            message: "top",
+            source: Some(Box::new(TestError {
+                message: "middle",
+                source: Some(Box::new(TestError {
+                    message: "bottom",
+                    source: None,
+                })),
+            })),
+        };
+
+        assert_eq!(
+            collect_error_source_chain(&error),
+            vec!["middle".to_string(), "bottom".to_string()]
+        );
+    }
+}