fix: address main and release workflow regressions

[markwylde]

Summary

• accept the updated macOS self-test success signal after the merged interceptor changes so the post-merge Tests workflow stops failing on main
• validate Linux arm64 release archives by checking binary architecture instead of trying to execute an arm64 binary on an amd64 GitHub runner
• add regression coverage for the Linux arm64 release validation path so this release break is caught in repo tests next time

Testing

• go test -v ./...
• go test -v -race -run TestRunSelfTestSucceedsWithInjectedProbe -count=1 -timeout 45s ./...
• go test -v -race -run TestRunSelfTestFailsWhenConnectNeverArrives -count=1 -timeout 45s ./...
• go test -v -race -coverprofile=coverage.out -timeout 4m ./...

Follow-up

• v1.3.2 was cut from the broken commit on main, so ship a fresh release after this merges instead of reusing that tag