Closes FCE-1874

Changes

Migrate to uv

Migrated to uv instead of poetry, because it's much faster (and state-of-art), which greatly improves the dev experience when e.g. building the dockerfiles (should also speed up CI).
Updated CI actions

Bump openapi-client version

Bumped openapi-python-client version, because old version was incompatible with newer httpx versions.
Regenerated the client and removed redundant model template.

Added Agent class

Added agent functionalities in fishjam/agent/.

Updated FishjamClient

FishjamClient can now be used to create agents:

with FishjamClient.create_agent(room_id) as agent:
    @agent.on_track_data
    def do_something(data: AgentResponseTrackData):
        pass
    await room_done()

Add transcription example app

Added an example app, which uses agents, similar to the js example.
It's a bit smarter, because it only prints entire turns, which improves the output.