Add inactivity timeout to ServerRedisTransport

- Add 5-minute inactivity timeout to prevent memory leaks
- Reset timer on each message received from client
- Clear timer on transport close
- Add comprehensive tests for timeout behavior
- Fix async/await in redisRelayToMcpServer calls

Sessions will now automatically shutdown after 5 minutes of no client activity.

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Co-Authored-By: Claude <[email protected]>

Author: jerome3o-anthropic