ci: fix windows go coverage package parsing

[RyshMan]

Problem

The nightly-full-windows workflow was failing in the Go tests with coverage step because Windows carriage returns were reaching go test package arguments and producing malformed import paths like github.com/Clyra-AI/gait/cmd/gait\r.

Changes

• emit LF-only bytes from scripts/list_go_test_packages.py so package output is stable across platforms
• defensively strip trailing \r values in the bash package-loading loops used by CI and the Windows nightly workflow
• preserve existing non-Windows behavior while hardening the Windows path

Validation

• ./gait doctor --json
• make prepush-full
• repo pre-push hook via git push (make prepush)