Add device agent library

Provide enrollment, elevated install, posture checks, keystore, and
system-tray helpers shared by the probo-agent binary.

Signed-off-by: Ludovic Vielle <ludovic@probo.com>

pkg/deviceagent/elevate/elevate_windows.go

@@ -0,0 +1,70 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+//go:build windows
+
+package elevate
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+
+	"go.probo.inc/probo/pkg/deviceagent/checks"
+)
+
+func runElevatedInstall(opts InstallOptions, enrollmentToken string) error {
+	args := []string{
+		"install",
+		"--server",
+		opts.ServerURL,
+		"--enrollment-token",
+		enrollmentToken,
+	}
+	if opts.ConfigDir != "" {
+		args = append(args, "--dir", opts.ConfigDir)
+	}
+
+	argList := make([]string, len(args))
+	for i, arg := range args {
+		argList[i] = "'" + escapePowerShellSingleQuoted(arg) + "'"
+	}
+
+	script := fmt.Sprintf(
+		`$p = Start-Process -FilePath %s -ArgumentList @(%s) -Verb RunAs -Wait -PassThru; if ($p.ExitCode -ne 0) { exit $p.ExitCode }`,
+		"'"+escapePowerShellSingleQuoted(opts.ExePath)+"'",
+		strings.Join(argList, ","),
+	)
+
+	candidates := checks.CommandCandidates("powershell.exe")
+	if len(candidates) == 0 {
+		return fmt.Errorf("command %q not available at expected absolute path", "powershell.exe")
+	}
+
+	out, err := exec.Command(
+		candidates[0],
+		"-NoProfile",
+		"-NonInteractive",
+		"-Command",
+		script,
+	).CombinedOutput()
+
+	return commandError(out, err)
+}