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]>

internal/app/cmd/config_test.go

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"os"
 	"path/filepath"
+	"strconv"
 	"testing"
 
 	"gitea.com/gitea/runner/internal/pkg/config"
@@ -38,7 +39,7 @@ func TestConfigCmdInitWritesTheMinimalConfig(t *testing.T) {
 
 	out, _, err := runConfigCmd(t, file, "init")
 	require.NoError(t, err)
-	assert.Contains(t, out, file)
+	assert.Equal(t, "wrote config file "+strconv.Quote(file)+"\n", out)
 	content, err := os.ReadFile(file)
 	require.NoError(t, err)
 	assert.Equal(t, config.Minimal, string(content))