Rename actor_standby_* arguments to Server Actor naming #1195

Follow-up to this discussion in #1169.

Actor Standby is now called Server Actors, and #1153 renames ActorClient.standby() to server() with standby() kept as a deprecated alias. The actor_standby_* arguments still use the old name:

• ActorClient.update and ActorCollectionClient.create: actor_standby_is_enabled, actor_standby_desired_requests_per_actor_run, actor_standby_max_requests_per_actor_run, actor_standby_idle_timeout, actor_standby_build, actor_standby_memory_mbytes, actor_standby_disable_standby_fields_override, actor_standby_should_pass_actor_input, plus actor_standby_tenancy from feat: Add server_tenancy parameter to Actor create and update #1169
• TaskClient.update and TaskCollectionClient.create: actor_standby_desired_requests_per_actor_run, actor_standby_max_requests_per_actor_run, actor_standby_idle_timeout, actor_standby_build, actor_standby_memory_mbytes

All of them apply to the async clients too. Add Server Actor names for these arguments, keep the actor_standby_* names as deprecated aliases until v4, and update the docstrings. Ship it all in one release together with #1153.

✍️ Drafted by Claude Code