HF RL Explorer

Issue: Streamline response handle type parameters and add synchronous receive for blocking actors

Issue: Streamline response handle type parameters and add synchronous receive for blocking actors: a task in LegoFlow-SWE (Harbor dataset). The new mail API ( self- mail(...).delay(...).request(...) , etc.) currently represents response types using a nested type list inside the response handle…

The task

The new mail API (`self->mail(...).delay(...).request(...)`, etc.) currently represents response types using a nested `type_list` inside the response handle template (e.g., `handle<type_list<A, B, C>>`). This extra nesting is unnecessary and complicates usage. The template parameters of the response handle should be…

Part of Lego-X/LegoFlow-SWE.