q1-is it possible set condition in auto action to run only in front-end?
Somewhat, yes. There's a substitution to determine location as shown on our substitutions tutorial page below.
www.joomlapolis.com/documentation/279-community-builder/tutorials/18353-using-substitutions-throughout-cb
It is as follows.
[cb:if application_context="frontend"]Frontend Only[/cb:if]
[cb:if application_context="administrator"]Backend Only[/cb:if]
You can combine it your condition to force some sort of behavior to be limited to a location. Example as follows.
[cb_test] Equal To 1
This would become the following.
[cb:if application_context="administrator"]0[cb:else][cb_test][/cb:else][/cb:if] Equal To 1
Now it should always fail the condition in backend.
3-set autoaction to onAfterRender for each user in that group to redirect to my custom Fabrik From that has send sms and if verify via user, then set that user to defult "Register" group in joomla
That's redirecting too early. You'd interrupt registration. You'd need to use the below which will fire when registration is completed.
onAfterSaveUserRegistration
I can't comment regarding the rest of your process as we've no support for SMS verification in any way.