Add theme switching with three modes (system/light/dark) using Tailwind v4
class-based dark mode. Theme preference is persisted in localStorage and
defaults to the system's prefers-color-scheme. All components updated with
dark: variants for consistent dark mode rendering including SVG elements.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add a dedicated /audit route displaying a chronological timeline of
orchestration events (state transitions, tool invocations, errors,
messages) grouped by session. Includes session selector, event type
filtering, URL deep-linking via ?session=id, and audit event capture
during chat streaming.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>