There doesn't seem to be a way to specify custom routing rules on the TV app.
The only way to add any config seems to be importing from file, however, shadowsocks config file only contains setting making it use custom rules, but doesn't contain the custom rules themselves.
One possible solution is to include custom rules in config file as well. Another is to add some kind of edit UI on TV app.
There doesn't seem to be a way to specify custom routing rules on the TV app.
The only way to add any config seems to be importing from file, however, shadowsocks config file only contains setting making it use custom rules, but doesn't contain the custom rules themselves.
One possible solution is to include custom rules in config file as well. Another is to add some kind of edit UI on TV app.