Fix deadlocks in tcpusb.Server.Close() and Socket.End() (#3)

* Initial plan

* Fix deadlock in tcpusb.Server.Close() by releasing lock before closing connections

Co-authored-by: codeskyblue <3281689+codeskyblue@users.noreply.github.com>

* Improve socket cleanup to skip when server is closed

Co-authored-by: codeskyblue <3281689+codeskyblue@users.noreply.github.com>

* Add blank line for better readability in Close method

Co-authored-by: codeskyblue <3281689+codeskyblue@users.noreply.github.com>

* Fix deadlock in Socket.End() by releasing lock before ending services

Co-authored-by: codeskyblue <3281689+codeskyblue@users.noreply.github.com>

* Remove extra blank line for consistency

Co-authored-by: codeskyblue <3281689+codeskyblue@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: codeskyblue <3281689+codeskyblue@users.noreply.github.com>