Add streaming support and refactor Chat UI

- Add run_stream method to AgentCore for streaming output
- Add base_url parameter to LLM clients for OpenRouter support
- Add xbot module for new agent implementation
- Refactor Chat.vue into composable + components (ChatHeader, ChatMessage, ChatInput, ChatSidebar, ChatAgentSelector)
- Add ChatStream handler for SSE streaming in Go server
- Add UseXBot field to chat request

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/internal/config/config.go

@@ -109,7 +109,7 @@ func InitDB(cfg *Config) (*gorm.DB, error) {
 	}
 
 	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
-		Logger: logger.Default.LogMode(logger.Info),
+		Logger: logger.Default.LogMode(logger.Silent),
 	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect database: %w", err)