Avoid rounding issues when checking Timeout values (#1700)

[nikolamilekic]

AsTimeout is called from the SshCommand constructor with Timeout.InfiniteTimeSpan. In this scenario the range check should never fail, but unfortunately it does in certain scenarios, due to a runtime or compiler bug (as soon as optimizations are turned off the issue miraculously disappears).

Closes#1700

[Copilot]

Pull Request Overview

This PR fixes a rounding issue in the AsTimeout extension method that was causing incorrect timeout validation failures. The issue occurred when checking Timeout.InfiniteTimeSpan values due to floating-point precision problems that were compiler/optimization dependent.

• Changed timeout calculation from double to long to avoid floating-point rounding issues
• Updated the range check to use integer comparison instead of floating-point comparison
• Enhanced the exception message to include the actual timeout value for better debugging

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[nikolamilekic]

It can be argued that the range check is completely unnecessary when called from the SshCommand ctor (as it is always called with Timeout.InifiteTimeSpan), and that the _commandTimeout field should be set in the constructor directly (instead of going through the CommandTimeout property, which triggers the range check). I didn't want to propose this change right away, as I'm unsure if your coding guidelines allow it.

[Rob-Hague]

I had half-fixed the tests that were asserting too strictly against the original commit, so I finished that and reverted to the original. Making the comparison on long rather than double feels safest for this problem

Thanks!