enhance: test on Windows and fix what it found (#1348)

Adds a weekly and on-demand workflow that runs the cross-compiled tests on Windows Server 2025 Core in a [dockur/windows](https://github.com/dockur/windows) QEMU VM, and fixes the Windows bugs it found in host and UNC paths, env handling, shell quoting, post-task scripts, health checks, checkout, action symlinks, step summaries, Git client certificates and docker mode from a Windows host.

Host-mode steps now emit UTF-8, `bash` falls back to Git's bash instead of the WSL launcher, the runner can run as a native Windows service, steps can keep background helpers with `RUNNER_TRACKING_ID`, and Windows arm64 binaries are released.

Fixes: https://gitea.com/gitea/runner/issues/1339
Fixes: https://gitea.com/gitea/runner/issues/637
Fixes: https://gitea.com/gitea/runner/issues/1172
Fixes: https://gitea.com/gitea/runner/issues/347
Reviewed-on: https://gitea.com/gitea/runner/pulls/1348
Reviewed-by: bircni <[email protected]>

act/container/docker_proxy_test.go

@@ -484,6 +484,10 @@ type probeClient struct {
 	containers []container.Summary
 }
 
+func (c *probeClient) Info(_ctx context.Context, _opts mobyclient.InfoOptions) (mobyclient.SystemInfoResult, error) {
+	return mobyclient.SystemInfoResult{}, nil
+}
+
 func (c *probeClient) Close() error {
 	return nil
 }
@@ -766,6 +770,9 @@ func TestDaemonSeesDir(t *testing.T) {
 }
 
 func TestRunnerContainerWorkdir(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("a runner container is Linux")
+	}
 	workdir := t.TempDir()
 	t.Chdir(workdir)
 	volume := container.MountPoint{Type: mount.TypeVolume, Source: "/daemon/_data", Destination: filepath.Dir(workdir)}