Reuse Third‑Party Tools as Native Dapr Agent Tools

[bibryam]

Context
Many agent frameworks routinely integrate third‑party tools (like CrewAI or LangChain) by wrapping them as native tools. This PR experiments with incorporating these into Dapr agents by lowering friction, reducing boilerplate, and making external tools first-class citizens.

#117

[bibryam]

I'm not sure yet how best to handle dependencies, specifically, which ones should be introduced at the Dapr Agent level versus those that should only come into play when a specific third-party tool (like CrewAI or LangChain) is actually used. If anyone has thoughts or patterns they've seen work well here, suggestions would be appreciated!