test(adapters): add empty response_item type and null assistant content tests

Verify that response_item with empty string type degrades to Partial in
Codex adapter, and Claude Code assistant message with null content
field parses cleanly.

Author: hsusul

crates/lore-core/src/adapters/claude_code.rs

@@ -991,4 +991,13 @@ mod tests {
             Some("   \n\t  ")
         );
     }
+
+    #[test]
+    fn parses_assistant_message_with_null_content_field() {
+        let jsonl = "{\"type\":\"assistant\",\"sessionId\":\"s1\",\"message\":{\"role\":\"assistant\",\"content\":null}}\n";
+        let session = ClaudeCodeAdapter::new().parse_str(jsonl, "null-assistant-content");
+        assert_eq!(session.status, crate::model::ParseStatus::Ok);
+        assert_eq!(session.messages.len(), 1);
+        assert_eq!(session.messages[0].parts.len(), 0);
+    }
 }

crates/lore-core/src/adapters/codex.rs

@@ -1329,4 +1329,12 @@ mod tests {
         assert_eq!(s.messages.len(), 1);
         assert_eq!(s.messages[0].parts.len(), 0);
     }
+
+    #[test]
+    fn parses_response_item_with_empty_string_type_and_notes_partial() {
+        let content = "{\"type\":\"response_item\",\"timestamp\":\"2026-08-11T10:00:00.000Z\",\"payload\":{\"type\":\"\"}}\n";
+        let s = CodexAdapter::new().parse_str(content, "empty-type");
+        assert_eq!(s.status, crate::model::ParseStatus::Partial);
+        assert!(s.notes.iter().any(|n| n.message.contains("unknown response_item")));
+    }
 }