feat: add chat protocol and runtime

[GabrielVasilescu04]

Description

Add protocol for chat protocol and runtime, enabling conversational agent implementations.

Development Package

• Add this package as a dependency in your pyproject.toml:

[project]
dependencies = [
  # Exact version:
  "uipath-runtime==0.2.1.dev1000420140",

  # Any version from PR
  "uipath-runtime>=0.2.1.dev1000420000,<0.2.1.dev1000430000"
]

[[tool.uv.index]]
name = "testpypi"
url = "https://test.pypi.org/simple/"
publish-url = "https://test.pypi.org/legacy/"
explicit = true

[tool.uv.sources]
uipath-runtime = { index = "testpypi" }