feat: move guardrail state to inner_state; add inputs to guardrail state

[andreiancuta-uipath]

Static args needs to read the agent inputs in the LLM node and in tool nodes. When these nodes are wrapped in the guardrail subgraph, the state is of type AgentGuardrailGraphState.

This PR modifies the guardrail subgraph state to contain the agent inputs, by creating a new "complete" state model using the input schema (similar to the main graph's state).

I also moved the guardrail-specific state properties inside inner_state, to avoid collisions with the agent input schema.

[andreitava-uip]

I don't really see an easier way of passing the agent input other than doing the same type inheritance at runtime shenanigans.
Possible alternative:

sandbox the input

We don't have the same restrictions here as we did for agent input. We could theoretically add an agent_input field to the SubGraph state. The problem is what we do later:

• we also need to add it to the main state. in init_node we could move fields from top level to this agent_input
• change wrapper/all other places that need the input to look into agent_input. This is easier than modifying the subgraph to extract them top level. Unfortunately this makes our things less reusable