use stable item IDs for Responses API calls

codex-rs/ext/image-generation/src/tests.rs

@@ -83,6 +83,7 @@ fn recent_image_fallback_selects_newest_images_in_chronological_order() {
             call_id: "mcp-call".to_string(),
         },
         ResponseItem::FunctionCallOutput {
+            id: None,
             call_id: "mcp-call".to_string(),
             output: image_output("mcp"),
         },
@@ -94,6 +95,7 @@ fn recent_image_fallback_selects_newest_images_in_chronological_order() {
             input: String::new(),
         },
         ResponseItem::CustomToolCallOutput {
+            id: None,
             call_id: "code-mode-call".to_string(),
             name: Some("exec".to_string()),
             output: image_output("code-mode"),
@@ -105,6 +107,7 @@ fn recent_image_fallback_selects_newest_images_in_chronological_order() {
             result: "generated".to_string(),
         },
         ResponseItem::FunctionCallOutput {
+            id: None,
             call_id: "orphan-call".to_string(),
             output: image_output("orphan"),
         },

codex-rs/ext/image-generation/src/tool.rs

@@ -248,9 +248,9 @@ fn recent_images(history: &[ResponseItem], count: usize) -> Vec<ImageUrl> {
                     ContentItem::InputText { .. } | ContentItem::OutputText { .. } => None,
                 }));
             }
-            ResponseItem::FunctionCallOutput { call_id, output }
-                if function_call_ids.contains(call_id.as_str()) =>
-            {
+            ResponseItem::FunctionCallOutput {
+                call_id, output, ..
+            } if function_call_ids.contains(call_id.as_str()) => {
                 image_urls.extend(output_image_urls(output));
             }
             ResponseItem::CustomToolCallOutput {