Create AI Agents Submodule

Problem/Motivation

We need a simple (initial) module to exemplify the modeler API implementation. Using the ai_agents's special modeler owner - would be a great intro.

Proposed resolution

Create a: react_flow_ai_agents submodule - that will use the existing elements (UI + Plugin Manager) - to properly show an AI Agent's structure via React Flow.

Perks are that usually it's limited to 2-3 components: Agent, Tools, Subagents - so these would fit the MVP to prove the concept of RF working.