refactor: merge ActionSummary and Thought fields to eliminate duplication

- Remove redundant ActionSummary field from PlanningResult struct
- Update parsers to use unified Thought field instead of duplicate fields
- Modify chat interface to display Thought instead of ActionSummary
- Update planner logging to use thought instead of summary
- Adjust prompt templates to use thought field consistently
- Switch test LLM service from UI-TARS to DoubaoVL
- Add default parameter handling for sleep tool

mcphost/chat.go

@@ -136,7 +136,7 @@ func (c *Chat) runPrompt(ctx context.Context, prompt string) error {
 		return c.handleToolCalls(ctx, toolCalls)
 	}
 
-	c.renderContent("Assistant", result.ActionSummary)
+	c.renderContent("Assistant", result.Thought)
 
 	return nil
 }