feat: Add STATE message handling for incremental sync support in universal source

## Summary

The universal source connector (`SourcePyAirbyteUniversal`) currently only forwards RECORD messages from the underlying PyAirbyte source. STATE messages are dropped, which means only full-refresh syncs are supported.

## Context

In `airbyte/cli/universal_connector/source.py`, the `read()` method filters messages to only yield RECORD types. STATE messages require per-stream format conversion between `airbyte_protocol.models` and `airbyte_cdk.models`, which adds complexity.

## Desired Behavior

- Forward STATE messages from the underlying source through the universal source connector
- Handle per-stream state format conversion between PyAirbyte's protocol models and the CDK models
- Enable incremental sync support for connectors wrapped by the universal source

## References

- Related PR: https://github.com/airbytehq/PyAirbyte/pull/982
- File: `airbyte/cli/universal_connector/source.py` (line 195)

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