feat: add realtime resolution support

[AdirAmsalem]

This PR lets realtime SDK users request 720p or 1080p streams at connect time while keeping existing behavior unchanged when no resolution is provided.
It also aligns realtime model FPS metadata with the current 30 FPS streaming experience so application UI and telemetry can reflect the realtime product correctly.

realtime_client = await RealtimeClient.connect(
    base_url=client.realtime_base_url,
    api_key=client.api_key,
    local_track=video_track,
    options=RealtimeConnectOptions(
        model=models.realtime("lucy-2.1"),
        on_remote_stream=on_remote_stream,
        resolution="1080p",
    ),
)

Validated with uv run pytest and uv run ruff check decart tests/test_models.py tests/test_realtime_unit.py.

---

Note

Medium Risk
Adds a new connect-time query parameter for realtime streams and changes advertised realtime FPS values to 30, which may affect client expectations and downstream UI/telemetry that relies on these fields.

Overview
Adds optional realtime resolution selection by extending RealtimeConnectOptions with resolution (720p/1080p) and appending it to the WebRTC connect URL when provided.

Updates realtime model registry metadata to advertise 30 FPS across lucy/mirage realtime models (tests adjusted accordingly), and bumps the package version to 0.0.38 with new unit tests verifying resolution URL behavior.

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