fix: close websocket self-connect connections

[222twotwotwo]

What this PR does:

Closes the upgraded WebSocket connection when a self-connect request is rejected, preventing the socket/resource from leaking on that path.

Also adds a regression test covering the upgraded self-connect branch and verifying that:

• the WebSocket upgrade succeeds
• session creation is skipped
• the upgraded connection is closed before returning

Which issue(s) this PR fixes:

Fixes #132

Special notes for your reviewer:

Tested with:

go test -run TestWSServeWSRequestClosesSelfConnectConn -count=1
go test ./... -count=1
go vet ./...
git diff --check

Does this PR introduce a user-facing change?:

NONE

[AlexStocks]

同理，给上游代码也来个PR

[222twotwotwo]

同理，给上游代码也来个PR

OK, done.