Deprecate RUNTIME_URL in favor of OH_WEB_URL
https://github.com/OpenHands/software-agent-sdk/pull/2429
cc
@calm-artist-7206 @straight-sundown-84319
This is related to deprecating some V0 env var in SDK - Tim, wdyt about this? Any particular stuff we need to change in the GUI to make sure this change doesn't break anything?