fix(tests): stop persistence cleanup from throwing on unlinked sockets

[Aforno]

Problem

Main CI failed on macos-15 release tests after merging #19:

SessionPersistenceTests.testRuntimeDoesNotPromoteProviderTelemetryForRejectedProtocol threw NSCocoaErrorDomain code 4 (“an-….sock” couldn’t be removed, POSIX ENOENT).

stop() already unlinks the event socket. Fixture teardown then called FileManager.removeItem on that same path. Debug and macos-14 passed; this showed up in the release suite.

Fix

• Put the test socket inside a short unique directory so bind/cleanup never touch the shared temp directory (and stay under Darwin’s unix-socket path limit).
• Unlink the socket and lock file directly instead of asking FileManager to delete them.
• Wait for the socket and for protocolMismatchDetected instead of a fixed 150ms sleep.

Verified locally: swift test, swift test -c release, ./script/check_repository.sh.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.