Conversation outline tab for dsh-better-sidebar

Key features

• For whomUsers who use DeepSeek Harness Web (npx@deepseek-ai/dsh web), want to browse quickly the current session structure, not used for rolling back long conversations.
• Session logHost reads only the current session log construction outline through ttx.sessionQuery (readsession/listEvents) and does not write back.
• The outline is structured by rotation - user message, helper response, tool call (continuous calls are automatically combined into a foldable group), compression check points, error lines, all shown in turn.
• One key jump - Click on any entry, automatically load history and scroll to the corresponding line of the chat view / track view.