Redesign ResponsePanel with SubQuestionSections component that parses answer markdown on ## Sub-question N: boundaries and renders per-sub-question cards with headers, ReactMarkdown body, and collapsible sources scoped to each section. Extract FlatResponse for backward compatibility when subQuestionSources is null. Add buildCitationLookupForSubq and processCitationsForSubq for per-sub-question citation lookup scope isolation. Add anchor links in ExtractedQuestionsDisplay that smooth-scroll to matching ResponsePanel sections. Pass subQuestionSources through LTTPage.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>