Add tray browser enrollment with region picker

The tray helper carried a ServerURL default that nothing read.
Unenrolled users can now open the console /enroll page from the
menu: US, EU, or self-hosted in production, or --server for dev.

Signed-off-by: Ludovic Vielle <ludovic@probo.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

pkg/deviceagent/tray/browser_test.go

@@ -0,0 +1,102 @@
+// 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 darwin || windows
+
+package tray
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestValidateBrowserURL(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		input   string
+		wantErr string
+	}{
+		{
+			name:  "accepts https",
+			input: "https://us.probo.com/enroll",
+		},
+		{
+			name:  "accepts http",
+			input: "http://localhost:3000/enroll",
+		},
+		{
+			name:  "accepts uppercase https",
+			input: "HTTPS://eu.probo.com/enroll",
+		},
+		{
+			name:    "rejects file scheme",
+			input:   "file:///etc/passwd",
+			wantErr: `unsupported URL scheme "file"`,
+		},
+		{
+			name:    "rejects javascript scheme",
+			input:   "javascript:alert(1)",
+			wantErr: `unsupported URL scheme "javascript"`,
+		},
+		{
+			name:    "rejects custom scheme",
+			input:   "slack://open",
+			wantErr: `unsupported URL scheme "slack"`,
+		},
+		{
+			name:    "rejects empty input",
+			input:   "",
+			wantErr: `unsupported URL scheme ""`,
+		},
+		{
+			name:    "rejects scheme-less input",
+			input:   "us.probo.com/enroll",
+			wantErr: `unsupported URL scheme ""`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			err := validateBrowserURL(tt.input)
+			if tt.wantErr == "" {
+				require.NoError(t, err)
+				return
+			}
+
+			require.Error(t, err)
+			assert.ErrorContains(t, err, tt.wantErr)
+		})
+	}
+}
+
+func TestOpenBrowser_RejectsDisallowedScheme(t *testing.T) {
+	t.Parallel()
+
+	err := openBrowser("file:///tmp/evil")
+	require.Error(t, err)
+	assert.ErrorContains(t, err, "cannot open browser URL")
+	assert.ErrorContains(t, err, `unsupported URL scheme "file"`)
+}