feat: enhance VLM response parsing and DOUBAO model support

- Fix JSON extraction logic by prioritizing brace counting method
- Add support for DOUBAO string array coordinate format
- Introduce IS_UI_TARS helper function for model type checking
- Add comprehensive tests for JSON parsing and coordinate handling
- Improve error handling with retry delays for LLM service failures

uixt/ai/planner.go

@@ -67,7 +67,7 @@ func (p *Planner) History() *ConversationHistory {
 }
 
 func (p *Planner) RegisterTools(tools []*schema.ToolInfo) error {
-	if p.modelConfig.ModelType == option.DOUBAO_1_5_UI_TARS_250428 {
+	if option.IS_UI_TARS(p.modelConfig.ModelType) {
 		// tools have been registered in ui-tars system prompt
 		return nil
 	}