refactor: refactor logging and server setup for clarity and structure (#64)

- Refactor server initialization calls in Run to use multiline construction style and explicitly pass options in HTTP mode
- Fix logic in Default to prevent redundant logger initialization
- Remove unused Logger function and introduce a Logger struct with Infof and Errorf methods for structured logging
- Add a New function for creating instances of the Logger struct

Signed-off-by: appleboy <appleboy.tw@gmail.com>

Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/64
Co-authored-by: appleboy <appleboy.tw@gmail.com>
Co-committed-by: appleboy <appleboy.tw@gmail.com>

operation/operation.go

@@ -44,17 +44,24 @@ func Run() error {
 	RegisterTool(mcpServer)
 	switch flag.Mode {
 	case "stdio":
-		if err := server.ServeStdio(mcpServer); err != nil {
+		if err := server.ServeStdio(
+			mcpServer,
+		); err != nil {
 			return err
 		}
 	case "sse":
-		sseServer := server.NewSSEServer(mcpServer)
+		sseServer := server.NewSSEServer(
+			mcpServer,
+		)
 		log.Infof("Gitea MCP SSE server listening on :%d", flag.Port)
 		if err := sseServer.Start(fmt.Sprintf(":%d", flag.Port)); err != nil {
 			return err
 		}
 	case "http":
-		httpServer := server.NewStreamableHTTPServer(mcpServer)
+		httpServer := server.NewStreamableHTTPServer(
+			mcpServer,
+			server.WithLogger(log.New()),
+		)
 		log.Infof("Gitea MCP HTTP server listening on :%d", flag.Port)
 		if err := httpServer.Start(fmt.Sprintf(":%d", flag.Port)); err != nil {
 			return err