Not sure if this has already been posted, but here is how I got both the new “Agent” and “IDE” to be installed at the same time.
Download both installers.
Perhaps backup \AppData\Local\Programs\Antigravity first just in case.
Uninstall any Antigravity versions currently installed (if any).
Install IDE first and change the default path to something like:
…\AppData\Local\Programs\AntigravityIDE
Install Agent afterwards. It will install in default path without option to change it.
…\AppData\Local\Programs\Antigravity
Now the two versions can coexist.
Hope this is helpfull for others who have problems getting the IDE to load after update to the new Agent version.