feat(ai/rsc): Implement bulked AI actions

[shuding]

This PR implements bulked AI action calls.

Currently if we have (note that action calls don't have await):

action1() // (state, action1) -> (diff, result); state = state + diff;
action2() // (state, action2) -> (diff, result); state = state + diff;
action3() // (state, action3) -> (diff, result); state = state + diff;

They will still be 3 sequential requests (also there's a bug regarding AI state in that case) mostly because the hidden state always depends on the previous response's diff.

With this PR, it will behave like:

action1() // (state, action1) -> (diff, result); state = state + diff;
action2() // (state, action2) -> queued
action3() // (state, action3) -> queued

    queue // (state, [action2, action3]) -> (diff, [result2, result3]); state = state + diff;

When the first one is executing, 2 and 3 will be queued and then sent together as one request and receive the results all together.